63 results about "Harmonic resonance" patented technology

The invention provides a real-time dynamic harmonic detection method and system for a traction power supply system, and relates to the technical field of harmonic detection, and the detection method comprises the following steps: collecting a voltage signal of the traction power supply system in real time, and dynamically tracking fundamental frequency fluctuation through a phase-locked loop technology; dynamically adjusting the data window length of FFT analysis; dynamically adjusting a frequency spectrum calculation kernel of the FFT; carrying out linear compensation on the detected harmonic phase; taking the preliminarily detected harmonic parameter as an initial value, and iteratively updating the harmonic parameter until convergence by minimizing a signal reconstruction error; dynamically adjusting a sampling interval according to the fundamental frequency fluctuation, and carrying out anti-aliasing processing by adopting a filter with a variable cut-off frequency; and constructing a matrix model containing a fundamental frequency fluctuation parameter, and calculating a real harmonic parameter through a least square method. According to the method, the detection defect of the fixed window FFT during frequency fluctuation can be systematically solved, and high-reliability real-time data support is provided for harmonic resonance suppression of the electrified railway.

Aiming at the stability problem caused by harmonic resonance of multiple parallel photovoltaic inverters, the invention provides a parallel inverter micro-grid-oriented adaptive virtual impedance remodeling harmonic resonance suppression method, which comprises a virtual impedance remodeling unit of a grid-connected inverter, a parameter adaptive adjustment unit and a power grid impedance online detection unit. The virtual impedance remodeling unit can improve the output impedance characteristic of the grid-connected inverter and inject a certain damping component into the micro-grid; and the parameter adaptive adjustment unit adaptively adjusts control parameters in the virtual impedance remodeling unit and the current adjustment controller according to the impedance parameters of the power grid so as to maintain the stability of a system control loop. The power grid impedance online detection unit provides power grid equivalent impedance as the input of the parameter adaptive adjustment unit. The three units work cooperatively to form a self-adaptive virtual impedance remodeling multi-inverter micro-grid harmonic resonance suppression strategy, so that the characteristics of a current loop are improved, the inverters can be kept stable under various grid impedance conditions, and the reliability of a multi-inverter micro-grid system is improved.

The invention relates to the technical field of cable line power distribution network harmonic resonance treatment, in particular to a global and local cooperative partition cooperative resonance suppression method and device. The method comprises the steps of determining a harmonic conductance sensitivity index of each node in a power distribution network according to a target power distribution network admittance matrix parameter, and performing node region division; performing modal analysis on the admittance matrix parameters to obtain modal impedance and participation factors; determining a global optimal virtual admittance instruction value according to the modal impedance, the participation factor and the voltage distortion rate; according to the global optimal virtual admittance instruction value and the voltage distortion rate, determining a regional optimal virtual admittance instruction value in the region; and determining a harmonic compensation current value according to the regional optimal virtual admittance instruction value and the harmonic voltage. According to the method, harmonic suppression is realized for the whole power distribution network by adopting a partition and cooperation mode, and meanwhile, for background harmonic injection change, external interference such as resonance center offset and the like can be effectively overcome, so that the optimal harmonic suppression effect is realized.

The invention discloses a method, a system, equipment and a medium based on a multi-composite ultrasonic penetration technology, and the method comprises the steps: generating high-frequency fundamental ultrasonic waves through a piezoelectric transducer array, and adjusting the frequency range to match the acoustic impedance characteristic of target soil; first, second and third harmonics are generated through the induction of a nonlinear medium in the fundamental wave propagation process, the phases of the harmonics are adjusted to realize coherent superposition, and the fundamental wave and the first, second and third harmonics are guided into a composite waveguide device for focusing and delay compensation to form a high-energy composite wave beam; a pulse interval is adjusted by adopting an intermittent emission strategy so as to inhibit energy attenuation in the soil; reflected wave spectrum components are monitored through an embedded acoustic sensor array, and driving parameters are dynamically adjusted; and residual ultrasonic energy is captured and fed back to a driving circuit to form a closed-loop energy utilization system. By integrating multi-order harmonic resonance and a dynamic frequency tuning technology, efficient transmission and deep penetration of ultrasonic energy in a complex medium are realized.

The invention discloses an offshore wind power harmonic transmission quantification method and system considering submarine cable insulation aging, and relates to the field of harmonic transmission characteristic analysis. The method comprises the following steps: dividing the insulation aging severity level of the submarine cable, and determining an insulation capacitance gain coefficient corresponding to each level of submarine cable; determining an actual capacitance gain coefficient of the insulation state of the submarine cable based on cable aging detection results regularly acquired by a power grid company; correcting the capacitance value of the submarine cable based on the actual capacitance gain coefficient; and establishing an equivalent circuit of an offshore wind power grid-connected system through the submarine cable line, estimating a grid-connected system harmonic resonant frequency causing harmonic current amplification according to the corrected submarine cable capacitance value, and estimating a harmonic current amplification coefficient of a grid-connected point under the harmonic resonant frequency of the grid-connected system. According to the method, the evaluation accuracy of the resonant frequency and harmonic amplification severity of the offshore wind power grid-connected system is remarkably improved, so that effective suppression of harmonic resonance amplification can be guided.

The invention relates to a fusion power supply harmonic suppression method based on an energy storage type STATCOM. The method comprises the following steps: determining a harmonic amplification factor K value; selecting and designing a proper discrete digital band-pass filter, and detecting a target frequency band and filtering characteristic sub-harmonics; the detected harmonic voltage amplitude and phase are used as references, an energy storage type STATCOM is adopted to output same-frequency and same-phase harmonic current, virtual damping is formed at a grid-connected point, a K value is used as a damping coefficient, the output harmonic current reference amplitude is determined, virtual harmonic damping is controlled, and harmonic resonance is suppressed. The virtual harmonic damping method for the energy storage type STATCOM is provided for accurate tracking of low-frequency harmonic and inter-harmonic voltage amplitudes and phases, the chain type STATCOM has the advantages of being high in high-voltage direct-hanging efficiency, high in redundancy fault-tolerant capability and the like and is suitable for high-voltage large-capacity scenes, virtual damping control achieves harmonic suppression by adjusting virtual damping at the harmonic frequency of a control structure, and the energy storage type STATCOM can be applied to high-voltage large-capacity scenes. And the system stability can be effectively improved while harmonic waves are treated.

The invention discloses a wind turbine generator impeller anomaly detection method and system based on sound vibration signal identification. According to the method, firstly, impeller response is collected through a microphone / vibration sensor, and a Mel spectrogram is generated; then, a Teager-Kaiser energy operator and self-correlation analysis are utilized, and under the condition of not depending on a rotating speed signal, the rotating period of the impeller is recognized, and frequency spectrum segmentation is carried out; calculating a cross-period Mel frequency spectrum dynamic deviation, and normalizing the cross-period Mel frequency spectrum dynamic deviation through an amplitude correction coefficient related to the rotating speed; generating a periodic coherent energy diagram by adopting an improved structural similarity algorithm; performing filtering enhancement by using a harmonic resonance template, performing morphological deconstruction and parameterization on an abnormal region in the graph, and extracting geometric features; and finally, calculating a comprehensive abnormal score based on the multi-dimensional features and realizing automatic early warning. According to the method, the problems of variable working condition interference and rotating speed dependence are effectively solved, and accurate and stable detection of early abnormality of the impeller can be realized.

A method and apparatus for evaluating light-weight cement (LWC) bond conditions in production well in presence or absence of the tubing. The apparatus includes a tool string that can be lowered into the casing or the tubing. The tool string includes a segmented transducer ring matrix to excite the surrounding medium resulting in vibrations. The tool string further includes an impedance measurement circuit that can determine natural resonance frequencies of the structural components. The impedance measurement circuit can determine certain non-harmonic resonance mode shapes for mechanical impedance measurements that are sensitive to the LWC bond conditions. A machine learning model can be used for segmented impedance measurements to correct effects from the tubing eccentricity inside the casing. Lab calibration generates bond index mapping table and the field logging impedance measurement data can be processed into the bond indexes to further evaluate LWC bond conditions.

The invention discloses a distributed energy storage cluster access power distribution network harmonic resonance analysis method, which comprises the following steps of: aiming at system elements in a power distribution network, respectively constructing harmonic impedance models considering d-axis and q-axis asymmetric dynamic states under a dq coordinate system; injecting a small disturbance component, constructing a small disturbance modal impedance matrix Z of the whole system based on a harmonic impedance model, and obtaining a node voltage variation matrix according to the small disturbance component and the small disturbance modal impedance matrix Z; decomposing an inverse matrix of the small disturbance modal impedance matrix into a form of multiplying a left eigenvector matrix, a diagonal eigenmatrix and a right eigenvector matrix; and substituting the decomposed small disturbance modal impedance matrix into the node voltage variation matrix to obtain a linear relationship between a modal voltage vector and a diagonal eigenmatrix and a linear relationship between the modal voltage vector and a modal current vector, and obtaining a critical modal and a corresponding resonant frequency according to an eigenvalue of the diagonal eigenmatrix.

The invention relates to the technical field of neuroacoustics, in particular to a personalized brain wave induced audio generation method and system, and the method comprises the steps: S1, extracting multi-dimensional features of an input audio signal, the extracted dimensions at least comprising a time domain feature, a frequency domain feature, a pitch feature, an emotion feature and a complex feature; s2, on the basis of the multi-dimensional features extracted in the step S1, parameters of four neuroacoustic induction mechanisms are calculated in parallel; and S3, according to the features obtained in the step S1 and the quadruple mechanism parameters obtained in the step S2, signals corresponding to the four mechanisms are fused through a weight distribution strategy and a signal synthesis formula to generate a final brain wave induction audio. The method has the advantages that four mechanisms of rhythm synchronization, harmonic resonance, neural oscillation coupling and binaural beat frequency effect are fused, parameters of all the mechanisms are dynamically adjusted by analyzing music characteristics, and efficient personalized brain wave induction is achieved.

The invention relates to a frequency conversion and moving blade combined control method, device and equipment of an induced draft fan and a medium. Comprising the steps that performance parameters and structure parameters of a target induced draft fan are obtained, the target induced draft fan is simulated based on the parameters, and an initial frequency conversion-moving blade combined operation strategy is generated; a resonance rotating speed prohibition interval of the target induced draft fan is determined, and a final frequency conversion-moving blade combined operation strategy is generated based on the initial frequency conversion-moving blade combined operation strategy and the resonance rotating speed prohibition interval; generating a rotating speed-moving blade opening mapping table based on the strategy and a first preset frequency conversion-moving blade coupling operation area of the target induced draft fan; and based on the first preset frequency conversion-moving blade coupling operation area, the second preset frequency conversion-moving blade coupling operation area, the preset multi-mode adjusting rule and the rotating speed-moving blade opening mapping table, frequency conversion and moving blade combined control is conducted on the target induced draft fan. Therefore, the problem that in the prior art, on the premise that the safety of an induced draft fan device body is guaranteed (frequency conversion harmonic resonance is avoided), the operation efficiency in the full working condition range cannot be optimized is solved.

The invention discloses a cluster admittance passivity control method based on inverter transformation, and the method comprises the steps: firstly obtaining an original anti-resonant frequency and an original sampling frequency of an inverter cluster; then, according to the original anti-resonant frequency, the original sampling frequency and the heterogeneous inverter, determining a target sampling frequency of the heterogeneous inverter; and then, according to the target sampling frequency, determining a filtering parameter of the heterogeneous inverter, and obtaining the configured heterogeneous inverter. And then, the configured heterogeneous inverters are put into an original inverter cluster, so that a target inverter cluster is constructed. The admittance phase of the target inverter cluster can be effectively controlled within a preset range. Through the mode, passive control in a broadband range is realized, dynamic harmonic resonance is effectively inhibited, and the interaction stability of the system is greatly improved. According to the embodiment of the invention, the stability and applicability of the inverter cluster can be improved while the complexity and cost of the system are reduced.

The invention relates to the technical field of Bluetooth headset control, and discloses an AI-based Bluetooth headset voice control method, system and equipment, and the method comprises the steps: obtaining real-time audio and voice signals, and obtaining frequency distribution characteristics through Fourier transform; and obtaining a matched peak value position set through multi-layer convolution operation and peak value detection. Single sound source feature subsets are extracted and clustered, and classified sound source groups are obtained; and carrying out fusion analysis on the resonance feature vectors, generating a preliminary tuning parameter set and an alternative list, and determining an optimal set. And a dynamic tuning scheme is obtained through smooth processing and weight adjustment. And after the voice signal instruction is matched, activating the scheme, adjusting the real-time audio, and outputting an optimized signal. According to the method, intelligent real-time audio optimization and multi-band adaptive adjustment based on the voice instruction can be realized, and the tone quality performance and auditory experience of the Bluetooth earphone in different scenes are improved.

The invention provides an anti-resonance device of an electromagnetic voltage transformer for a GIS (Gas Insulated Switchgear). The anti-resonance device comprises a sub-harmonic anti-resonance circuit, a fundamental harmonic anti-resonance circuit and a higher harmonic anti-resonance circuit, the anti-resonance circuits are connected in parallel and then are connected to the PT opening triangle side. According to the sub-harmonic anti-resonance circuit, when sub-harmonic resonance occurs in a system, a nonlinear saturable reactor reaches a saturated state, and flowing current causes instantaneous loss, so that generation of the sub-harmonic resonance is inhibited; the fundamental harmonic anti-resonance circuit generates an electric field when current passes through an inductive element, and charges of the electric field are accumulated in a capacitor; two ends of the mutual inductor are connected in parallel or in series with a capacitor to form an LC series resonance circuit; the capacitor destroys resonance conditions in a loop to suppress fundamental harmonic waves; according to the high-order harmonic anti-resonance circuit, when voltage rise and current increase are detected, a high-power resistor in a secondary circuit enables zero sequence voltage to be in short circuit, inductance generated by mutual inductor overload changes resonance conditions in the secondary circuit, and high-order harmonics are eliminated. And the safety of the system is improved.

The invention discloses a method, a device and equipment for determining broadband harmonic resonance of a power distribution network containing a grid-connected converter and a medium, and relates to the technical field of harmonic resonance. The method comprises the following steps: injecting a harmonic source into each node of the power distribution network at a plurality of preset frequencies in a sweep frequency manner, obtaining harmonic quantities under different frequencies, and determining harmonic amplification degree indexes under different frequencies; forming an amplification factor frequency characteristic curve with the frequency as the horizontal axis and the harmonic amplification degree index as the longitudinal axis, and determining a resonance amplification area; determining an original disturbance frequency harmonic severity index according to the resonance amplification region; determining secondary resonance severity indexes under different frequencies according to the harmonic quantity; and according to the original disturbance frequency harmonic severity index, the secondary resonance severity index and the harmonic amplification degree index, determining a harmonic danger region of each node and each branch in the power distribution network, and finally determining a harmonic resonance danger position in the power distribution network. By defining the secondary resonance severity index, the accuracy of harmonic quantization of the whole power distribution network can be improved.

An optimization design method of a double-tuned filter for a converter station comprises the following steps: calculating a total impedance function Z (omega) of the double-tuned filter; representing two tuning points of the filter through a full impedance function Z (omega) of the double-tuned filter, and defining an intermediate angular frequency of the double-tuned filter; the value of a high-voltage side capacitor C1 is determined according to the fundamental wave reactive compensation quantity QS1, and the values of L1, L2 and C2 are solved; and calculating the fundamental wave power loss of the medium resistor R of the double-tuned filter and the harmonic amplification coefficient H (omega) of the characteristic harmonic voltage of the AC filter of the converter station. And with the filtering performance, the resonance-free risk and the equipment investment cost as constraint conditions, the values of L1, L2 and C2 are optimized by adopting an optimization algorithm. According to the method, the optimal design process of an existing double-tuned filter topological structure for the converter station is analyzed in detail by considering the filtering effect and the harmonic amplification effect and combining the circuit principle, the filtering effect of the double-tuned filter for the converter station can be improved, and the harmonic resonance or harmonic amplification risk is avoided.

The application provides an online identification method for harmonic resonance of a power system, comprising the following steps: collecting voltage waveform data and current waveform data at a preset common coupling point in the power system, pre-processing to obtain waveform difference degree, performing multiple transformations on the collected voltage waveform data and current waveform data to obtain current complex matrix and voltage complex matrix of a fundamental wave and each harmonic; determining a fundamental wave and a total harmonic impedance amplitude array of the common coupling point according to an equivalent model of the power system; calculating power factors of the fundamental wave and each harmonic, and obtaining a power factor array after screening; and determining that harmonic resonance occurs in the power system when the waveform difference degree, the harmonic number array and the power factor array simultaneously satisfy a preset resonance condition. The application combines the similarity of the collected waveforms, harmonic impedance and power factors of multiple parameters, and only needs voltage and current waveform data at the PCC point to identify the harmonic resonance in the power system.

The present application relates to a kind of distribution network user side loop resonance active suppression method and system, by real-time monitoring and calculating harmonic distortion rate and key frequency point amplitude, whether the system is in resonance state is intelligently judged.When potential resonance risk is detected, actively start resonance suppression device work, actively destroy resonance occurrence condition, the resonance suppression device has two control modes: damping enhancement mode is by input resistor to improve system damping, effectively suppress resonance energy accumulation;Damping enhancement and frequency offset collaborative mode, in combination with damping enhancement mode, then by adjusting capacitor switching capacity, change system inherent resonance frequency, make it deviate from current harmonic frequency, to avoid resonance, the control algorithm of resonance active suppression device is realized by PID algorithm.The present application is suitable for the low-frequency harmonic resonance problem caused by nonlinear load in user side low-voltage distribution network, and is suitable for the comprehensive treatment of resonance problem in industrial, commercial and civil power system.

Embodiments provide a moldable warming device, including: a heating disc; a pair of stimulation vibration generators; a coupling device; and an ocular and periocular treatment platform, the ocular and periocular treatment platform being head mounted and forehead stabilized. The moldable warming device is configured to sequentially and alternately apply therapeutic warmth to meibum within each Meibomian gland duct in all four eyelids and, and further configured to simultaneously apply tuned harmonic resonance or non-resonance frequency stimulation vibration across the contour of the entire surface of the user's four eyelids and periorbital structures and across the contour surface of the user's nasal bridge area through the user's nasal bone, after the heating disc has lowered the lipid viscosity within each Meibomian gland duct, to induce expression of shear thinned and liquified meibum from each Meibomian gland duct in all four eyelids to improve the lipid layer of the surface of the user's eye tear film.

The present disclosure is directed to an electrical power generation system that includes at least one DC energy source, at least one electrical generator that generates an alternating current power supply signal, and at least one harmonic resonance oscillator and at least one flywheel operably coupled between the at least one DC energy source and the at least one electrical generator.

The invention belongs to the technical field of regional power grid electric energy quality treatment, and discloses a cross-power-grid harmonic resonance suppression method, system and device and a medium, and the method comprises the steps: deploying an active filter, and executing local harmonic treatment; on the basis of a local harmonic suppression result, the operation state of the active filter is evaluated, the residual capacity of the flexible resources in the regional power grid is called, and a cooperative harmonic suppression mechanism for cooperative work of the active filter and the flexible resources is constructed; and synchronously executing local harmonic suppression and collaborative harmonic suppression mechanisms, monitoring the total harmonic distortion rate of the regional power grid in real time, performing iterative optimization adjustment on the installation position and capacity of the active filter by using a particle swarm optimization algorithm, and outputting an optimal suppression scheme. According to the invention, through optimizing the harmonic suppression strategy, the total harmonic distortion rate of the power system is reduced, so that the harmonic suppression effect is improved; and a chance constraint method is adopted to ensure that the method has good robustness and adaptability under different power grid operation conditions.

The present disclosure provides a modal analysis-based multi-grid-connected inverter harmonic resonance determination method and system, which belongs to the technical field of multi-grid-connected inverter harmonic resonance determination, and comprises: obtaining a system node admittance matrix based on a pre-constructed multi-grid-connected inverter equivalent model; obtaining a system modal impedance based on the system node admittance matrix by using a modal analysis method, wherein the system modal impedance is the reciprocal of the eigenvalue of the system node admittance matrix; calculating a damping ratio based on the obtained system modal impedance by using a half-power bandwidth method; and performing resonance degree calculation based on the system modal impedance and the damping ratio to realize determination of multi-grid-connected inverter harmonic resonance.

The invention relates to a compressor torque compensation method and variable frequency air conditioning equipment. The method comprises the steps that vibration acceleration frequency spectrums of a compressor in multiple directions under adjacent operation frequencies are obtained, the vibration acceleration frequency spectrums comprise vibration acceleration amplitude values under a fundamental wave frequency and a harmonic wave frequency, and according to the vibration acceleration amplitude value change trend of the fundamental wave frequency or the harmonic wave frequency under the adjacent operation frequencies, the vibration acceleration frequency spectrums of the compressor in multiple directions are obtained; and judging whether the compressor generates fundamental wave resonance or harmonic wave resonance at the current operation frequency, determining a torque compensation strategy according to the resonance mode and the resonance direction under the condition of judging that the compressor generates fundamental wave resonance or harmonic wave resonance at the current operation frequency, and executing the torque compensation strategy in a resonance frequency range containing the current operation frequency, and torque compensation current is determined, and torque compensation is conducted on the compressor according to the torque compensation current. By the adoption of the method, directional and accurate vibration suppression can be achieved, and the compensation effect is remarkably improved.

The invention provides a power system resonance suppression method and device, equipment and a storage medium, and relates to the technical field of power quality analysis and control. The method comprises the following steps: acquiring electrical signals of a plurality of nodes in a power system, and identifying a source node which generates harmonic resonance currently and a corresponding resonant frequency based on the electrical signals; a load redistribution scheme is generated with the aim of destroying the resonance condition of the source node, the scheme is used for transferring at least one load under the source node to other nodes so as to change the system impedance of the source node, and the system impedance is equal to the parallel equivalent value of the impedance of all the loads under the source node; a load redistribution scheme is performed to suppress harmonic resonance. Resonance suppression can be realized only by optimizing the existing network load distribution, the system transformation cost is remarkably reduced, the additional operation loss is reduced, the instability risk is controlled, meanwhile, the advantages of rapid response, high adaptability and the like are achieved, and effective technical support is provided for constructing a safe and flexible novel power system.

The present invention provides a real-time dynamic harmonic detection method and system for a traction power supply system, which relates to the technical field of harmonic detection. The detection method includes the following steps: collecting voltage signals of the traction power supply system in real time, and dynamically tracking the fundamental frequency fluctuation through a phase-locked loop technology; dynamically adjusting the data window length of the FFT analysis; dynamically adjusting the spectrum calculation kernel of the FFT; and linearly compensating the detected harmonic phase; taking the preliminarily detected harmonic parameters as initial values, and iteratively updating the harmonic parameters until convergence by minimizing the signal reconstruction error; dynamically adjusting the sampling interval according to the fundamental frequency fluctuation, and performing anti-aliasing processing by using a filter with a variable cut-off frequency; constructing a matrix model containing fundamental frequency fluctuation parameters, and calculating the true harmonic parameters by using the least squares method. The method of the present invention can systematically solve the detection defects of the fixed-window FFT in the case of frequency fluctuation, and provides high-reliability real-time data support for the harmonic resonance suppression of electrified railways.

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

The embodiment of the invention relates to the technical field of harmonic resonance suppression of an energy storage converter, and provides a harmonic resonance suppression method and system for a network construction type energy storage converter, which abandons the traditional thought of relying on fixed parameters, and perceives the stability of a grid-connected system online in real time through a non-intrusive resonance state observer. The resonance state observer can accurately identify the frequency and the damping ratio of the most unstable resonance mode in the current system to form a real-time diagnosis report, and based on the real-time diagnosis report, a virtual impedance controller with optimal parameters is further dynamically synthesized, so that the real-time diagnosis report is obtained. The center frequency of the virtual impedance can accurately lock the identified resonant frequency, and the damping strength of the virtual impedance is adaptively adjusted according to the severity of resonance (namely the deterioration degree of the damping ratio), so that the problem of invalidation or deterioration of suppression caused by the time-varying of the impedance of the power grid and the drifting of a resonance point in the traditional method is solved; and the stability of the converter in a dynamic change power grid environment is ensured.

The invention provides a ship valve electric device control system and a construction method thereof, and belongs to the technical field of ship valve control. According to the electric device control system, a frameless torque motor is used as a driving unit, and parameter identification, self-adaptive control, smooth switching and safety protection units are integrated, so that motor parameter drift and inverter nonlinear disturbance can be compensated in real time; according to the control method, a linear active-disturbance-rejection self-adaptive control framework is constructed through dead-beat direct torque flux linkage control and an extended Kalman filter algorithm, a full-rank identification model is established through time-sharing injection of current, accurate parameter identification is achieved in combination with an improved particle swarm algorithm, a harmonic resonance suppression and ramp function switching strategy is adopted, and the control precision is improved. And the torque ripple and the mode switching impact are reduced. The problems that a traditional ship valve device is low in torque density, narrow in speed regulation range and weak in anti-interference capacity are solved, the special working condition requirements of low-speed heavy load, high-speed position regulation and the like of a ship valve are met, control precision is high, and stability and reliability are high.

The invention relates to a power distribution network user side loop resonance active suppression method and system, which intelligently judges whether the system is in a resonance state or not by monitoring and calculating a harmonic distortion rate and a key frequency point amplitude in real time. When a potential resonance risk is detected, the resonance suppression device is actively started to work, resonance generation conditions are actively damaged, and the resonance suppression device has two control modes: a damping enhancement mode improves system damping by inputting a resistor, and resonance energy accumulation is effectively suppressed; a damping enhancement and frequency deviation cooperative mode is combined with a damping enhancement mode, and the natural resonant frequency of a system is changed by adjusting the switching capacity of a capacitor to deviate from the current harmonic frequency, so that resonance is avoided, and a control algorithm of the active resonance suppression device is realized by a PID algorithm. The method is suitable for the low-frequency harmonic resonance problem caused by the nonlinear load in the user-side low-voltage power distribution network, and is suitable for comprehensive treatment of the resonance problem in industrial, commercial and civil power systems.

The present application relates to the technical field of neuroacoustics, in particular to a personalized brainwave induction audio generation method and system, comprising: step S1, extracting multi-dimensional features of an input audio signal, the extracted dimensions including at least time domain features, frequency domain features, pitch features, emotion features and complexity features; step S2, based on the multi-dimensional features extracted in step S1, parallelly calculating parameters of four neuroacoustic induction mechanisms; step S3, according to the features obtained in step S1 and the four-mechanism parameters obtained in step S2, fusing signals corresponding to the four mechanisms through a weight distribution strategy and a signal synthesis formula to generate a final brainwave induction audio. The present application has the advantages that: four mechanisms of rhythm synchronization, harmonic resonance, neural oscillation coupling and binaural beat effect are fused, mechanism parameters are dynamically adjusted through analysis of music features, and efficient personalized brainwave induction is realized.