102 results about "Frequency response analysis" patented technology

The invention discloses a method for measuring dielectric properties of diamond anvil cells in situ and belongs to the technical field of electromagnetic measurement under high voltage. The method comprises the following steps of firstly, assembling the diamond anvil cells, i.e. respectively forming round electrodes on the anvil surfaces of two diamond anvil cells, wherein an insulating layer is arranged on the inner side wall of a sample cavity of a composite insulating cushion; secondly, performing measurement, i.e. using a frequency response analysis meter to obtain relation patterns between an impedance real part and an impedance virtual part under different pressures; and finally, performing data processing, i.e. using Zview software and an electromagnetic metering formula related to dielectric properties to obtain the relative dielectric constant epsilon r, the dielectric constant real part epsilon', the dielectric constant virtual part epsilon'', the loss tan theta and the like. The shapes and the positions of the electrodes are fixed, and meanwhile, correction is performed because of the influence of fringe effect on a measuring result; and the prepared composite insulating cushion ensures complete insulation of the inner wall of a voltage cavity, so that the method for precisely measuring the dielectric properties of a material in situ under high voltage is realized.

The invention discloses an acceleration frequency response analysis-based body floor optimal design method, which comprises the following steps of: acquiring a body floor design input condition; establishing a CAD (Computer Aided Design) model; establishing a finite element model; performing mode CAE (Computer Aided Engineering) analysis on the finite element model to perform mode test on a white body sample; performing benchmarking; checking and verifying the finite element model according to a benchmarking result; searching a region of a large vibration displacement of the white body floor in the finite element model according to a mode CAE analysis result, extracting an inspection point from the region, and performing acceleration frequency response analysis on the inspection point; and modifying the floor design input condition according to the acceleration frequency response analysis result until the vibration response requirement is met. The method has the characteristics of shortening the development time, reducing the development cost, improving the entire noise, the vibration and the comfort, reducing the error between the finite element model and the floor sample and keeping high design quality.

The invention discloses power transformer fault intelligent diagnosis technology, method and device, and relates to power transformer fault intelligent diagnosis technology and method and the intelligent diagnosis device based on the technology and the method. The intelligent diagnosis device comprises a data acquisition and transmission part and a management and display part. The intelligent diagnosis device is characterized in that power transformer fault intelligent diagnosis technology and method comprise a dissolved gas in oil analysis and diagnosis technology, a partial discharge online monitoring and diagnosis technology, an infrared temperature measurement diagnosis technology, a vibration analysis and diagnosis method, a frequency response analysis and diagnosis method, a winding temperature indication diagnosis method and a low voltage impulse response test diagnosis method, and fault intelligent diagnosis is carried out. According to the invention, a multi-parameter state monitoring method is used, and multiple fault intelligent diagnosis technologies and methods are integrated; valuable data which can be used to diagnose a fault and find out the position are given; the cause of the defect is eliminated; the shutdown time and the cost are reduced; and the purposes of power transformer intelligent monitoring and intelligent diagnosis are realized.

The invention provides a power transformer winding fault diagnosing method, by which winding deformation fault diagnosis is performed through combination of frequency response analysis (FRA) and empirical mode decomposition (EMD). According to the power transformer winding fault diagnosing method, on the basis of energy change information in each interval during a winding deformation fault as well as the adaptive decomposing capacity of the empirical mode decomposition (EMD), a fault energy characteristic quantity of a winding is extracted to establish a fault energy database; the fault energy characteristic quantity is compared with an energy curve of a transformer winding without a fault; the change trend of the characteristic energy shows the working state of the transformer; and the method is used for establishing a mapping relationship between an intrinsic mode function of the winding deformation and an intrinsic mode function of an FRA signal and establishing an integrated fault diagnosis analysis system based on characteristic energy information of the EMD. The integrated fault diagnosis analysis system can accurately know a basic rule of the change of the transformer winding deformation energy and provides a new research way for determining the type and the degree of a transformer fault and estimating the developmental trend of the fault.

The invention relates to a motor rotor turn-to-turn short circuit fault detection method based on frequency response analysis. The method comprises the following steps of: S1, establishing a frequency response analysis model, which is a passive linear two-port network, wherein N over-the-ground distributed capacitances C with unit length are connected between an input end and an output end of the two-port network in parallel; S2, sequentially inputting sine-wave voltage signals Vs with different frequencies; S3, digitally recording over-the-ground voltage signals Vi (n) and Vo (n) on two ends of the two-port network; S4, obtaining a transfer function H (n) being equal to 20log [Vo (n)/ Vi (n)]; and S5, plotting frequency responses into a curve according to frequency, and computing a correlation coefficient between frequency response curves measured by two times, wherein if the correlation coefficient is smaller than 1, a turn-to-turn short circuit is proved to exist in a motor rotor winding. According to the motor rotor turn-to-turn short circuit fault detection method based on frequency response analysis, the accuracy for judging the motor rotor turn-to-turn short circuit fault can be improved, and the reliability of motor operation is improved.

Disclosed is a satellite momentum wheel vibration disturbance test and a data interpretation method. The method comprises the steps of firstly building a harmonic wave superposition mathematical model through actual measurement of disturbing force generated by a momentum wheel; then building satellite finite element models of satellites in an orbit state and multiple kinds of ground vibration disturbance test states respectively, adopting a frequency response analysis method to calculate vibration disturbance overall response of each harmonic wave to sensitive equipment in all kinds of satellite states, choosing a ground test state with minimum analysis result difference of the satellites in the orbit state to carry out the momentum wheel vibration disturbance test and conduct actual measurement of a vibration disturbance of a momentum wheel to the sensitive equipment; finally amending the analysis result of the orbit sate through postprocessing of the measurement result so as to assess and verify the accuracy and validity of the design of the satellite momentum anti-wheel vibration disturbance. According to the satellite momentum wheel vibration disturbance test and the data interpretation method, simulated analysis is adopted to guide test program design and result interpretation, the influences of each harmonic wave component of momentum wheel disturbing force to the sensitive equipment respectively can be assessed, the calculated amount is small, and convenience is brought to project implementation.

The winding testing unit provides systems and methods for determining normal and/or abnormal characteristic signatures of same-voltage windings residing in a device, such as transformer, without the need for a comparison to past historical data. A plurality of characteristic signatures [H(f)'s] are determined for each of a plurality of windings. A plurality of differential characteristic signatures [H(f)'s] are then determined from a plurality of H(f) pairs selected from the plurality of H(f)'s. The differential H(f)'s are compared and at least one significant asymmetry is identified between the differential H(f)'s.

The present invention discloses a model correction method integrated with frequency, vibration modes and frequency response functions. A multi-satellite distributor has complex space configuration characteristics of multiple branches, high center of mass and low frequency, and model correction integrated with frequency, vibration modes and frequency response functions is performed on a established space finite element model. The method specifically comprises the steps of performing preliminary modal analysis on the preliminarily established space finite element model, performing modal and frequency response analysis on the model after primary screening, performing comparison with test results of modal tests and sine sweep tests, performing further correction according to the comparison results, setting the model to be in a flight state, and obtaining a flight state space finite element model. The model can be used for performing dynamic response analysis, or be used for performing full-scale dynamic characteristic and full-scale dynamics response calculation on basic rockets.

The invention provides a statistical energy analysis-based ship cabin noise forecasting method. The method comprises the steps of 1, preliminarily building a statistical energy analysis-based ship cabin noise forecasting model by utilizing ship drawing data; 2, performing local detail optimization on an emphatically assessed cabin and load region in the built model, and constructing an external auxiliary sound cavity; 3, determining a vibration acceleration load and a sound power load of equipment by utilizing an experimental test; 4, performing calculation by utilizing the experimental test or a formula to determine loss factors in a steel plate and the sound cavity; 5, building a microacoustic analysis model of an outfitting material structure by utilizing a transfer matrix method, and obtaining acoustic parameters of an outfitting material through sound absorption and insulation analysis; 6, setting frequency response analysis as a 1/3 octave frequency, and setting a calculation frequency to be 31.5Hz-8kHz; and 7, performing ship cabin noise forecasting analysis by applying statistical energy analysis. The efficiency and precision of ship cabin noise forecasting can be effectively improved; and the method can be applied to ocean platform and ship cabin noise forecasting and control.

The invention discloses a strength analysis method of an automotive cantilever structural part. The strength analysis method comprises the following steps: a finite element model is obtained by performing modal analysis on the cantilever structural part and a part borne by the cantilever structural part; the finite element model and actually measured modal are subjected to benchmarking; an actually measured acceleration spectrum is loaded to the finite element model after benchmarking for frequency response analysis, and results of stress distribution at different frequencies are obtained. According to the method, the finite element model subjected to benchmarking with the actually measured modal is taken as the base model, the actually measured acceleration spectrum is loaded for frequency response analysis, the results of stress at different frequencies are output, the vibration factor can be mainly considered, the stress distribution state of the cantilever structural part better meeting a field test state is obtained finally, and the analysis precision is higher.

The invention discloses a transformer winding deformation quantitative diagnosis method based on model correction. The method comprises the steps as follows: on the basis of detecting the deformation of a transformer winding by a frequency response analysis method, calculating the frequency response function of an equivalent circuit model of a normal transformer winding, and comparing the frequency response function with the frequency response data of a faulty transformer winding to determine the frequency response function deviation; constructing a frequency response function sensitivity matrix by an adjoint network method to describe the quantitative corresponding relationship between the frequency response function deviation and the equivalent circuit model parameter correction; selecting an appropriate frequency based on linear correlation to reconstruct a maximum linearly-independent sensitivity matrix; and determining the parameter correction when the frequency response function deviation reaches the minimum through iterative model parameter correction, and analyzing the winding deformation state and the diagnosis accuracy based on the parameter correction. By adopting the method of the invention, the position, degree and type of winding deformation can be judged accurately and quantitatively, and the diagnosis accuracy of transformer winding deformation can be effectively improved.

The invention provides a transformer winding deformation diagnostic method based on discrete wavelet transform. The transformer winding deformation diagnostic method is characterized in that the discrete wavelet transform method is applied to the frequency response analytic diagnosis of transformer winding deformation. The transformer winding deformation diagnostic method comprises performing decomposition process on a measured waveform obtained by virtue of frequency response analysis and a reference waveform at a plurality of layers by virtue of discrete wavelet transform, and then performing mathematical statistical analysis by use of the processed smooth data and diagnosing the deformation degree of a transformer winding according to a corresponding criterion. Such a diagnostic mode is capable of effectively reducing the errors of a traditional diagnostic mode due to white noise interference during frequency response measurement and some local relatively strong interference points and accurately diagnosing the deformation degree of the transformer winding, and therefore, a new judgment method is provided for estimating transformer fault types and the development trend of faults.

The invention discloses a transformer winding deformation intelligent detection method based on sweep frequency impedance curve identification. A short-circuit impedance method and a frequency response analysis method are combined, a transformer winding equivalent circuit model is established and acquisition of a transformer winding sweep frequency impedance curve is performed; the method comprises the following steps: under the condition that a sampling resistor R and a voltage U of the sampling resistor R are known, a current I flowing through a winding can be obtained through a formula I =U/R, and a sweep frequency impedance method wiring mode which effectively combines a short circuit impedance method and a frequency response analysis method can be obtained; during testing, one side of a transformer winding is short-circuited by using a wire, and sine sweep signals with the frequency of 10Hz-1MHz are injected into the head end of the transformer winding on the other side; and theresistance values of sampling resistors RC1 and RC2 in the test system are 50 omega, so that the current flowing through the non-short-circuited side is shown in the description. According to the invention, the transformer winding deformation is intelligently detected according to the change condition of the element parameter value, the situation that the transformer winding deformation excessively depends on experienced professionals is avoided, the analysis conclusion is unified, and great convenience is brought to the maintenance decision.

The invention relates to a call wire random power fluctuation calculating method based on a load fluctuation characteristic. First, a correlation model of load fluctuation and call wire random power fluctuation is established, the correlation model of load fluctuation and call wire random power fluctuation is deduced and analyzed in a detailed mode according to dynamic differential analysis of call wire power fluctuation, system frequency response analysis, call wire power fluctuation analysis based on system frequency analysis and call wire fluctuation analysis based on the load fluctuation characteristic. Two zone frequency response coefficients and corresponding weight coefficients are acquired, two zone load distributions f (x) and f (y) are acquired according to practical operation data, Monte Carlo sampling simulating test is carried out according to the distributions, results are subjected to statistics and analysis, and then call wire random power fluctuation conditions are calculated. The method is high in reliability, accurate and efficient, and powerful support can be provided for quick restraining of call wire random power fluctuation and improving of call wire electricity transmission capacity.

The invention discloses a method for diagnosing inter-turn insulation faults of dry type electric reactors on the basis of frequency response analysis. By the aid of the method, the problem of incapability of timely detecting inter-turn insulation breakdown and occurred inter-turn short-circuit for existing dry type electric reactors in the prior art can be solved. The method includes applying voltage signals at different frequencies to A-phase windings, B-phase windings and C-phase windings of each three-phase dry type hollow electric reactor (2) by the aid of a frequency response analyzer (9), and acquiring electric reactor impedance amplitude-frequency response characteristic curves under the condition of the various voltage signals at the frequencies; comparing the electric reactor impedance amplitude-frequency response characteristic curves acquired at the second step under the condition of the various voltage signals at the frequencies to electric reactor impedance amplitude-frequency response characteristic curves when the three-phase dry type hollow electric reactor is put into operation, and diagnosing that inter-turn short-circuit faults of the three-phase dry type hollowelectric reactor already occur if correlation coefficients of each electric reactor impedance amplitude-frequency response characteristic curve under the condition of the voltage signals at the frequencies and the corresponding electric reactor impedance amplitude-frequency response characteristic curve are smaller than 1. The frequency ranges of the voltage signals are 0-1000 thousand hertz. Themethod has the advantages that the inter-turn insulation faults are detected in advance and are handled in advance, and accordingly burning loss of the dry type hollow electric reactors can be effectively prevented.

A high-temperature seal having in-situ integrity monitoring capability includes a quantity of dielectric material sealing an interface between adjacent structures and an electrical transmission line embedded within the dielectric material. A signal injection port is provided for exciting the transmission line with an excitation signal. One or more sample ports are provided for sampling the transmission line to obtain signal samples resulting from the excitation signal. The sample port(s) are adapted for connection to a signal analyzer adapted to analyze the signal samples for indications of seal integrity problems. Using a technique such as time domain reflectometry or frequency response analysis, the transmission line can be monitored for changes in characteristic impedance due to changes in seal dielectric constant and/or disruption of the transmission line. Such evaluation provides useful information for making determinations about seal integrity in a manner that permits safe seal operation and minimization of resultant stress modes.

The embodiment of the invention discloses an audio frequency adjusting system and an audio frequency adjusting method. The audio frequency adjusting method comprises the following steps of: outputting a frequency response test signal to a to-be-tested voice broadcasting device; receiving a first output audio frequency which is generated by the to-be-tested voice broadcasting device according to the frequency response test signal; performing response analysis on the first output audio frequency to generate a group of equalizer parameter suggested values; adjusting a group of equalizer parameters according to the equalizer parameter suggested values so that an original sound signal generates a sound test signal according to the equalizer parameters; instantaneously generating a second output audio frequency through the to-be-tested voice broadcasting device according to the sound test signal; judging whether the auditory effect of the second output audio is close to the original sound signal or meets the demand of user; and adjusting the equalizer parameters if the auditory effect is not close to the sound test signal or does not meet the demand of user. The audio frequency adjusting system and method disclosed by the embodiment of the invention can adjust audio frequency fast to achieve the purpose of conforming to the auditory effect.

An oxide-ion sensor includes an oxygen electrode, a sense electrode and a saturated (reference) electrode. The sense electrode is operated at a substantially constant current for determining an instantaneous value of a dissolved oxide-ion concentration in the molten salt electrolyte. The saturated electrode is used to determine a reference value of the dissolved oxide-ion concentration in the molten salt electrolyte. A dissolved oxide-ion concentration in the molten salt electrolyte is continuously monitored in-situ during the molten-salt based electrochemical reduction process by determining an equilibrium potential between the sense electrode and the saturated electrode with the sense electrode carrying a small current in a circuit that is completed using the oxygen electrode. In another embodiment, the dissolved oxide-ion concentration in the molten salt electrolyte is continuously monitored in-situ by determining an electrochemical impedance of the molten salt electrolyte using a pair of bare current-carrying conductors and a frequency response analyzer.

The invention relates to an aircraft dynamics monitoring method based on frequency response analysis, and belongs to the technical field of aeroelastic test. The aircraft dynamics monitoring method based on frequency response analysis comprises the following steps: step one, acquiring the reference frequency fri and the inspection frequency fti of an aircraft structure in an ith-order mode; and step two, acquiring frequency weigh errors of an aircraft flutter characteristic according to a weight error formula. According to the external field dynamics monitoring method based on frequency response analysis, dynamics monitoring can be carried out on an external field by simple frequency examination through application frequency response function analysis and mode weight error analysis, thus,the dynamic characteristic of an aircraft in a using process is obtained and is applied to assessment of the flutter characteristic of the aircraft, and finally, the use envelope of the aircraft is given to guarantee flight safety of the aircraft.

The invention provides key equipment during the power transmission and transformation process of an electrical power system. According to the invention, the key equipment conducts the tasks of voltage transformation, power allocation, power transmission and the like. The reliable operation of the key equipment is directly related to the safe and stable operation of the electrical power system. In order to timely find out the potential accidents of a transformer and improve the working efficiency, a frequency response analysis (FRA) method-based power distribution transformer winding deformation online monitoring system is developed. Meanwhile, the software of the monitoring system is programmed by adopting the LabVIEW. In this way, the online monitoring function of transformer windings is realized. According to the above system, a sensor is arranged at the bushing tap of a transformer and a pulse signal of the transformer is injected via the sensor for parameter measurement. Therefore, frequency response curves that reflect the deformation states of transformer windings can be obtained. Through comparing the frequency response curves, the deformation states of transformer windings can be effectively determined.

The invention discloses a virtual automatic control experimental system and a design method of the virtual automatic control experimental system. The virtual automatic control experimental system comprises a time domain analysis method experiment module, a root-locus method experiment module, a frequency domain analysis method experiment module, a system correction experiment module and an open experiment module, wherein the time domain analysis method experiment module comprises a first-order system time domain analysis module, a second-order system time domain analysis module and a high-order system time domain analysis module; the root-locus method experiment module comprises a second-order system root-locus analysis module, a third-order system root-locus analysis module and a high-order system root-locus analysis module; the frequency domain analysis method experiment module comprises a typical link frequency response characteristic analysis module and a composite system frequency response analysis module; the system correction experiment module comprises a series connection lead correction module, a series connection lag correction module, a series connection lag-lead correction module and a PID correction module; the open experiment module comprises a water level control module, an elevator control module and a traffic lamp control module. By means of the virtual automatic control experimental system and the design method, a user can design and simulate an automatic control experiment, the efficiency of the automatic control experiment is improved, limitation of hardware equipment is avoided, an experimenter can conveniently have a study, and shortcomings in a traditional experiment are overcome.

The invention discloses a power system frequency response analysis method considering frequency space distribution, which analyzes the distribution law of system imbalance power among units and reaches a conclusion that the imbalance power distribution comprises two processes of impact distribution and inertia distribution. The distribution law of the system imbalance power among units is realized, a conclusion is reached that the imbalance power distribution mainly comprises two processes of impact distribution and inertia distribution, and a simplified admittance matrix is adopted to realize the above two distribution processes. As is shown by simulation analysis, the method can effectively reflect influences brought to the frequency by the unit distribution features and the change relation between the system frequency and the active power. On the premise of ensuring high calculation precision, the calculation efficiency is greatly enhanced compared with the existing model and the method can be used for large-scale system long-time dynamic frequency analysis.

The invention belongs to the technical field of structural vibration reduction dynamics calculation methods, in particular to a cyclic symmetry structure frequency response analysis method of an additional dry friction damper. The cyclic symmetry structure frequency response analysis method of the additional dry friction damper comprises the following specific operation steps: S1, establishing a structural member and damper sector kinetic equation, s2, establishing a sector finite element model; obtaining a sector quality and rigidity matrix; s3, performing degree-of-freedom compression on thesector model by applying a modal synthesis method; s4, adding a complex constraint boundary condition to the compressed model; s5, performing time domain representation of dry friction force; S6, solving a nonlinear equation set by using a mixed time-frequency method. According to the cyclic symmetry structure frequency response analysis method of the additional dry friction damper, storage resources and calculation time are greatly saved, the calculation time saving ratio is equivalent to the saving ratio of the storage resources, the number of nonlinear degrees of freedom participating in iteration is reduced, the convergence risk is effectively reduced, and an efficient and robust frequency response solving algorithm is formed.

The invention discloses a wireless headset noise reduction method and system, a wireless headset and a computer readable storage medium. The method comprises the steps of obtaining first environmental noise collected by a left headset and second environmental noise collected by a right headset; performing frequency response analysis on the first environmental noise and the second environmental noise to obtain a balance curve; and calculating a first EQ compensation parameter corresponding to the first environmental noise and a second EQ compensation parameter corresponding to the second environmental noise according to the balance curve, so that the left earphone utilizes the first EQ compensation parameter and the right earphone utilizes the second EQ compensation parameter to carry out noise reduction processing. According to the noise reduction method provided by the invention, left and right ear gain balance of the wireless earphone is realized.