121 results about "Frequency spectrum analysis" patented technology

The invention discloses an unmanned aerial vehicle detection method based on multi-band radio spectrum analysis, and the method can recognize the flight control behaviors of a target, such as hovering, cruising or hovering, through the extraction of a signal track and the introduction of a behavior modeling mechanism, and effectively overcomes the defect that the prior art lacks the dynamic behavior analysis capability. A multi-node synchronization mechanism and a TDOA positioning method are combined, so that high-precision traceability of a target space position is realized; meanwhile, risk level assessment is carried out based on signal features, a track mode and a space region, so that the system has intelligent early warning capability. According to the whole scheme, a full-link unmanned aerial vehicle detection method from multi-frequency receiving, frequency spectrum identification, behavior judgment, target positioning to risk output is constructed, and the problems of single frequency band, rough identification means, lack of tracking and evaluation capability and the like in the prior art are effectively solved; and the practicability and the accuracy of the unmanned aerial vehicle detection system in a complex airspace environment are remarkably improved.

The invention discloses an intelligent temperature control mattress system based on multi-mode sensing and adaptive learning, and the system comprises a data collection module which is used for collecting a mattress surface vibration signal, a mattress surface temperature and a mattress surrounding environment parameter; the data analysis module is used for performing deep analysis on the time-frequency domain features according to a biological recognition model to obtain human body or non-human body classification, performing self-learning to obtain body movement changes, accurately recognizing various typical sleeping postures and filtering out error data; and the model prediction module is used for monitoring the physiological parameters of the user according to the spectral analysis, inputting the physiological parameters, the collected temperature and the parameters of the surrounding environment of the mattress into a temperature control model composed of three neural networks of LSTM, GNN and Transform for comprehensive analysis and decision making, and outputting an optimal temperature control strategy. According to heart rate changes or body heat fluctuations, the sleep stage and the sleep and waking time are intelligently recognized, and therefore sleep environment adjustment better conforming to the human body rhythm is achieved.

The invention belongs to the technical field of hydropower station monitoring and early warning, and particularly relates to a hydropower station intelligent inspection and fault early warning linkage method, which comprises the following steps: arranging a redundant sensor network at key equipment parts, synchronously acquiring pressure, flow, vibration and water turbidity data, establishing a flow-pressure loss reference relationship, and calculating real-time pressure-flow ratio deviation; performing spectral analysis on the vibration signals, extracting characteristic frequency band energy, performing collaborative study and judgment in combination with a turbidity change trend, and ensuring data credibility through data cross validation of main and auxiliary sensors; performing time sequence difference operation on the pressure-flow ratio deviation to obtain a change rate, fusing vibration-turbidity abnormal performance, and comprehensively diagnosing water diversion blockage or foreign matter invasion; early warning levels are divided according to the deviation and the change rate, corresponding response measures are triggered, response actions are executed according to a preset risk priority sequence, and linkage control of the whole process from state sensing, anomaly recognition, fault diagnosis to intelligent response is achieved.

The invention provides a motor multi-band vibration suppression method and a motor multi-band vibration suppression device based on electromagnetic-mechanical cooperative regulation and control. According to the method, vibration signals are collected in real time, and spectral analysis is carried out to identify vibration frequency distribution; dividing the vibration signal into a low-frequency band, a middle-frequency band and a high-frequency band according to a spectral analysis result, and respectively corresponding to a mechanical vibration source, an electromagnetic excitation source and a structural noise source; a control strategy is dynamically selected based on a vibration frequency band, a low-frequency band triggers a mechanical regulation and control module to output a reverse force to perform vibration suppression, a middle-frequency band triggers an electromagnetic control module to optimize a current waveform and a PWM modulation mode, and a high-frequency band starts a cooperative control strategy of the electromagnetic and mechanical control module; through real-time communication between the controller and each module, vibration feedback signals are continuously monitored, and control parameters are dynamically adjusted according to working condition changes so as to maintain the vibration suppression effect. According to the invention, through cooperative adjustment of electromagnetic control and a mechanical structure, active suppression of vibration of the motor in multiple frequency bands is realized.

The invention relates to the field of charging pile use, and discloses a charging pile use frequency analysis method based on charging frequency data, which comprises the following steps: acquiring charging frequency original data of a plurality of charging piles at different time periods and different dates, performing structured processing in combination with a time label, and constructing a charging behavior data set containing a time dimension label; introducing a sliding window algorithm and a periodic spectrum analysis method, and performing frequency feature extraction on the charging behavior data set; using a density peak clustering algorithm to classify the use frequency matrixes of different charging piles under the same time scale, and identifying use preferences and active features of the charging piles under various typical time scenes; based on a lightweight time sequence neural network structure, a frequency fluctuation sensing mechanism is introduced; and predicting the use condition of the charging pile in a future time period based on the trained frequency model in combination with regression prediction and an anomaly detection algorithm. The method has the advantage of improving operation scheduling.

The invention relates to the technical field of concrete detection, in particular to a concrete protective layer void detection method and system based on a detachable piezoelectric ceramic sensor and an electromechanical impedance resonance technology. The detection method comprises the following steps: temporarily fixing a detachable piezoelectric ceramic sensor on a detection point on the surface of a concrete structure; applying an alternating-current sweep-frequency voltage to excite the piezoelectric ceramic sensor, and obtaining an electromechanical impedance signal frequency spectrum; the electromechanical impedance signal frequency spectrum is analyzed, the frequency of a local defect formant is obtained, and according to the frequency of the local defect formant, geometric parameters of a void area are estimated through a defect size and frequency relation model; and moving the sensor and repeatedly detecting other detection points. The detection method has high efficiency and flexibility, and detection can be realized in any environment; the single-point detection speed is high, the efficiency is high, baseline data is not needed for detection, the anti-interference performance is high, and rapid positioning and quantitative evaluation of void damage can be achieved.

The invention provides a method and system for diagnosing high-frequency magnetic disturbance in a quasi-ring symmetrical star simulator, and relates to the technical field of star simulators, and the method comprises the steps: designing the three-dimensional size of a magnetic probe body in combination with a physical research target and a vacuum chamber space limiting condition, and preparing a magnetic probe entity adaptive to an experimental environment; designing a magnetic probe array space layout according to the triangular magnetic configuration characteristics of the CFQS star simulator to obtain a positioned magnetic probe array; a positioned magnetic probe array is utilized to construct a signal transmission link, and a calibration qualification system is formed; generating a multi-channel time domain voltage signal set according to a calibration qualified system; and performing frequency response correction on the multi-channel time domain voltage signal set in combination with a transfer function database, analyzing a disturbance mode structure and a propagation direction through time-frequency spectrum analysis and array phase difference, and finally outputting three-dimensional magnetic disturbance evolution characteristics. The three-dimensional high-frequency magnetic disturbance measuring device has the beneficial effects that the three-dimensional high-frequency magnetic disturbance measuring capability is realized, multi-channel high-fidelity signal acquisition can be realized, and the experimental data quality and the physical analysis capability are improved.

The invention relates to an active sonar echo signal phase jump compensation method and device based on a synchronous serial number, and belongs to the technical field of underwater acoustic signal processing. The method comprises the following steps: adding a synchronous serial number into a wet end signal to form an expansion matrix; transmitting the extended signal to a signal processor and windowing the extended signal; traversing a synchronous serial number in the windowing signal, and detecting the continuity of the synchronous serial number to judge whether packet loss exists or not; if packet loss exists, positioning a packet loss position and performing zero padding operation; and finally, carrying out fast Fourier transform on the zero-filled signal to obtain a spectral analysis result. According to the method, accurate identification and phase compensation of the packet loss position are achieved through the synchronous serial number, the method is suitable for underwater acoustic single-frequency signals, and when the packet loss rate does not exceed 2.5%, spectrum sidelobes can be effectively restrained, and the peak value of the spectrum sidelobes is reduced to be within 10% of the packet loss state. The method has the advantages of being clear in principle, easy and convenient to operate and high in calculation efficiency, is suitable for real-time signal processing, and remarkably improves the reliability and efficiency of target detection.

The invention discloses a coal mine tunneling roadway advanced geological exploration and ground stress inversion method, particularly relates to the technical field of seismic signal processing in geophysical exploration, and is used for solving the problems of geological exploration signal distortion and insufficient stress inversion precision caused by strong noise interference of tunneling equipment in the prior art. Rock mass vibration signals are collected through an optical fiber sensor arranged on a roadway wall, equipment noise characteristics are identified through spectral analysis, a quantitative mapping relation between working condition parameters and noise characteristics is established, a noise reference time period is determined according to the quantitative mapping relation, a spatial coherence characteristic template is constructed, high-coherence noise components are inhibited through template comparison, and the noise reference time period is determined according to the spatial coherence characteristic template. Finally, the geological structure and stress field distribution in front of the working face are inverted based on the purified seismic wave signals, a stress concentration area and a disaster risk area are identified, the signal-to-noise ratio of the seismic signals in the strong noise environment and the reliability of the geological inversion result are effectively improved, and accurate technical support is provided for safe mining of a coal mine.

The invention provides a multi-modal fusion unmanned aerial vehicle identification method and system, and the method comprises the steps: obtaining a radio signal, an image signal and a sound signal of an unmanned aerial vehicle; performing feature extraction on the radio signal based on a blind source separation algorithm and adaptive filtering to obtain radio features; performing feature extraction on the image signal based on image super-resolution reconstruction and a double-flow feature extraction network to obtain image features; performing feature extraction on the sound signal based on spectral analysis and harmonic feature extraction to obtain an audio feature; fusing the radio feature, the image feature and the audio feature to form a multi-modal fusion feature; and performing identification based on the multi-modal fusion features to obtain an unmanned aerial vehicle category identification result. By adopting the scheme, the accuracy, reliability and environmental adaptability of unmanned aerial vehicle identification can be remarkably improved.

The invention provides a die cutting equipment error optimization method and system based on group collaboration, and relates to the technical field of die cutting machines, and the method comprises the steps: carrying out the spectrum analysis of a frequency characteristic curve of each piece of die cutting equipment, so as to divide an initial interference group; establishing a virtual spring damping network in the initial interference group, regarding each die cutting device in the initial interference group as a mass point, and determining a spring stiffness coefficient and a damping coefficient according to an actual distance between adjacent mass points; determining vibration mode characteristics of each die cutting device according to the spring stiffness coefficient and the damping coefficient, and converting a control signal generated according to the vibration mode characteristics into a parameter adjusting variable by using a preset control algorithm; and determining a vibration coupling relationship according to the collected vibration energy data of the initial interference group after the initial processing parameters are adjusted according to the parameter adjusting quantity, and determining an optimal production takt and a parameter compensation value according to the vibration coupling relationship. The technical problem that in the prior art, due to vibration coupling of a die cutting equipment group, the machining error cooperative control difficulty is large is solved.

The invention relates to the field of electrical variable measurement, in particular to an insulating layer compactness detection method for a mineral cable, which comprises the following steps: firstly, acquiring a time domain reflection signal of the cable, and carrying out denoising pretreatment by utilizing synchronous average and wavelet transform; and then, carrying out spectrum analysis on the discrete signal segments, calculating a spectrum centroid offset rate to determine high-frequency energy attenuation, and constructing a dynamic compensation gain coefficient according to the high-frequency energy attenuation. And then, improving a traditional layer stripping algorithm by using the gain coefficient, eliminating calculation deviation caused by transmission loss, and accurately reconstructing characteristic impedance distribution along the cable. And finally, by comparing the deviation between the reconstructed impedance and the nominal impedance, positioning and judging the abnormities of the compactness of the insulating layer of the cable and the eccentricity defect of the cable core are realized.

The invention discloses a compressor multi-working-condition feature extraction method based on valve movement acoustic emission, and belongs to the technical field of compressors, and the method comprises the following steps: S1, synchronously collecting compressor valve acoustic emission signals and piston displacement data by using an acoustic emission sensor and a rotating speed encoder, and constructing a time alignment joint signal sequence; s2, calculating a real-time phase according to a piston displacement crankshaft angle, enveloping an energy change rate by combining an acoustic emission signal, and dividing four stages of a compression cycle; s3, extracting the multi-dimensional time-frequency characteristics of the acoustic emission signals in each stage; and S4, inputting the multi-dimensional features into a pre-training auto-encoder, and generating low-dimensional fusion feature vectors to represent operation features. According to the compressor multi-working-condition feature extraction method based on valve movement acoustic emission, acoustic emission and displacement combined modeling is adopted to improve the working condition sensing precision, multi-dimensional features are extracted by means of wavelet packet transformation and spectral analysis fusion to strengthen micro working condition recognition, and the method adapts to multiple typical working conditions and is good in robustness and adaptability.

The invention provides a rapid positioning method and system for excitation system power cabinet draught fan faults, and the method comprises the steps: collecting the operation parameters of an excitation system power cabinet draught fan in real time in a preset time period, and the operation parameters comprise the draught fan rotating speed, the bearing temperature, the vibration frequency, the current value and the voltage value; analyzing the operation parameters by using a threshold value judgment method and a trend analysis method, and judging whether the excitation system power cabinet fan has a fault or not; when the excitation system power cabinet draught fan breaks down, sound signals of the draught fan are collected, spectral analysis is conducted on the sound signals of the draught fan, and a spectral analysis result of the draught fan is obtained; and determining the fault type and the fault position of the fan based on the spectral analysis result of the fan. According to the technical scheme provided by the invention, the fan fault monitoring precision and efficiency are improved.

The invention relates to an intelligent sound field calibration method and system, and the method comprises the steps: transmitting sweep frequency signals in a preset frequency range to a plurality of microphone collection positions in a sound field, collecting echo signals through each microphone, and constructing an acoustic feature database based on the echo signals; extracting a relative position relationship between microphones and corresponding echo signal features from the acoustic feature database, constructing a sound field spatial topological graph and dividing acoustic partitions based on the relative position relationship and the echo signal features, and determining response weights of the partitions; based on the acoustic characteristic database, a frequency spectrum analysis algorithm is adopted to identify and mark howling frequency points, and a preliminary frequency response curve is generated in combination with the howling frequency points and the response weights of the acoustic partitions; adjusting the initial frequency response curve according to historical preference data of the user to generate a target frequency response curve; and applying the target frequency response curve to the audio output path to output the audio signal. The method has the effect of improving the accuracy of sound field calibration.

The invention discloses an electric reactor vibration detection method, device and equipment and a medium, and relates to the technical field of electric power detection, and the method comprises the steps: obtaining an electric drive signal converted from the mechanical vibration of an electric reactor; based on the electric driving signal, controlling the working state of the passive vibration measurement circuit so as to perform frequency multiplication processing and amplitude modulation on the input radio frequency excitation signal to obtain a modulated harmonic signal; performing spectral analysis on the modulated harmonic signal to obtain carrier component and sideband component information, and determining a vibration frequency estimation value of the reactor based on the carrier component and sideband component information; performing inversion calculation based on the sideband component information, and determining a duty ratio estimation value corresponding to the electric driving signal; wherein the duty ratio estimated value represents the conduction time proportion of the passive vibration measurement circuit controlled by the electric driving signal; and querying a preset calibration relation based on the vibration frequency estimation value and the duty ratio estimation value to obtain the vibration acceleration of the reactor. The method can obtain an accurate detection result.

The application belongs to the technical field of zinc powder purification, and provides a condensation and sedimentation system for zinc powder purification, which comprises the following steps: collecting a time sequence of original radiation intensity of a condensation chamber, performing frequency spectrum analysis through fast Fourier transform, calculating energy values of high and low frequency band frequency domain signals, solving a signal coherence factor and calculating a transmittance attenuation coefficient, constructing a metal thin film radiation compensation model based on a long short-term memory network, inputting the attenuation coefficient and the time sequence of original radiation intensity to output a corrected real temperature of the condensation chamber, expanding an inference layer of a full connection neural network structure, outputting a calibrated attenuation coefficient through the inference layer, selecting an effective attenuation coefficient input model by comparing a deviation threshold value, dynamically responding to temperature measurement nonlinear attenuation caused by zinc film deposition, guaranteeing production continuity and product quality of zinc powder purification, adapting to industrial multi-working condition operation requirements, being convenient to operate and controllable in cost.

The invention discloses a jitter suppression method and system for an AGV. The method comprises the steps that a rotor speed signal and a torque instruction signal of a permanent magnet synchronous motor of the AGV are collected; performing discretization sampling on the rotor speed signal to obtain a discrete speed signal; performing spectral analysis on the discrete speed signal to extract a corresponding vibration spectrum, and obtaining a main frequency point where resonance occurs; inputting the discrete speed signal into a high-pass filter to extract a component required by active damping suppression of a vibration frequency point, carrying out discretization differential on the discrete speed signal to obtain an acceleration signal, and carrying out band-pass filtering on the acceleration signal by adopting a band-pass filter to obtain a component required by acceleration feedback suppression; the cut-off frequency of the high-pass filter and the center frequency and bandwidth of the band-pass filter are determined by main frequency points; and a compensation torque signal is obtained according to the jitter component and the component required for acceleration feedback suppression, so that jitter caused by resonance of the AGV is suppressed according to the compensation torque signal.

The invention discloses a dual-pressure evaporation organic Rankine cycle control method and system. The method comprises the steps that the difference of high-pressure side and low-pressure side operation parameters is collected to detect and recognize the pressure distribution unbalance degree, and a dual-pressure compensation regulation factor is generated; analyzing the high-voltage side operation parameter spectrum to identify a dominant fluctuation frequency band, and generating a frequency deviation degree to determine a pressure regulation key point; a priority adaptation strategy combination is screened based on a pressure regulation and control key point retrieval strategy library, and after a reference control sequence is formed, a composite regulation and control signal is generated through dual-pressure compensation regulation factor time sequence adjustment and gain adjustment; monitoring the pressure distribution unbalance degree and the response coupling strength of the dual-pressure compensation regulation factor to identify pressure instability precursor characteristics and execute a composite regulation signal, and performing gradient jump analysis to generate a control efficiency index; the pressure distribution unbalance degree is dynamically tracked, the pressure fluctuation attenuation rate is analyzed and recognized through oscillation attenuation, the stability margin is generated in combination with the control efficiency index and the pressure fluctuation attenuation rate, and a graded execution instruction is output to achieve dynamic balance of pressure distribution.

The application provides a whole vehicle sound source noise target setting method, system, device and medium, relates to the NVH technical field, and the method comprises the following steps: firstly, obtaining the sound pressure level noise data of a test vehicle under a target working condition through a first bench test; then, respectively determining the sound transmission functions of the test vehicle and a target vehicle through a second bench test; then, performing frequency spectrum analysis on the sound pressure level noise of the test vehicle to obtain target sound pressure level noise in a specific frequency range. Combined with the sound pressure level noise of the test vehicle and the sound transmission function thereof, the sound source noise of the test vehicle is calculated; further, the target sound pressure level noise and the sound transmission function of the target vehicle are utilized to determine the sound source noise of the target vehicle; finally, according to the sound source noises of the test vehicle and the target vehicle, the sound source noise target value of the target vehicle is set. The application can effectively solve the problem that the bench test is inconsistent with the actual performance of the whole vehicle, and improve the accuracy and rationality of the sound source noise target setting.

The invention discloses an improved M3C circulating current suppression method based on a three-phase static coordinate system, and belongs to the technical field of power electronic converter control. The method comprises the following steps: identifying four dominant frequency components (omega1-2omega2, 2omega1-omega2, omega1 + 2omega2 and 2omega1 + omega2) in the M3C circulating current through spectral analysis (omega1 is a power frequency side angular frequency, and omega2 is a low frequency side angular frequency); under a three-phase static coordinate system, proportional resonance controllers are independently arranged on the nine bridge arms to generate circulating current suppression voltage signals, and the four frequency components are suppressed; and meanwhile, a zero-sequence suppression voltage signal is generated through a proportional controller, so that the amplitude of zero-sequence current with the frequency of 3 omega 1 and 3 omega 2 does not exceed 5% of the rated current of the bridge arm. According to the method, coordinate transformation and a phase-locked loop are not needed, the internal loop current of the bridge arm is effectively suppressed, bridge arm current distortion is reduced, and the method is suitable for a power frequency-low frequency alternating current interconnection scene.

The present application relates to the technical field of ripple suppression, and discloses a ripple suppression method and system for a high-voltage electrical network of a vehicle, the method comprising: obtaining a bus voltage ripple waveform under a target operating condition, determining a peak frequency through frequency spectrum analysis; establishing an equivalent impedance model of a high-voltage loop to identify a resonance frequency range; when the peak frequency falls within the resonance frequency range, solving an equivalent inductance increment required by the high-voltage loop under the constraint of a switching frequency characteristic point set and a minimum allowable frequency interval; implementing inductance tuning through equivalent length adjustment of a wire harness or a series inductor device on a high-voltage connection wire harness at a front drive and a rear drive port; re-measuring a ripple index after tuning and comparing it with a threshold value, and if the ripple index does not meet the threshold value, updating the inductance increment and repeating the tuning process. Through frequency domain feature extraction, impedance modeling and frequency avoidance constraint, the present application improves the adaptability and consistency of ripple suppression under different conditions and parameter conditions.

The application provides a flexible direct current transmission line single-end fault distance measurement method based on frequency domain analysis, which comprises the following steps: collecting a reclosing end real-time voltage value and a reclosing end real-time current value, determining equivalent resistance values of each point along a line based on the reclosing end real-time voltage value and the reclosing end real-time current value; performing frequency spectrum analysis on the equivalent resistance values of each point along the line to generate frequency spectrums of each point along the line; respectively calculating a center of gravity frequency of each point along the line based on the frequency spectrums of each point along the line; and sorting the center of gravity frequencies of each point along the line, and determining a fault distance by selecting a line position corresponding to the smallest center of gravity frequency. The method realizes flexible direct current transmission line single-end fault distance measurement, and improves positioning accuracy and stability of flexible direct current transmission line single-end fault distance measurement.

The invention discloses a woven fabric density detection method and a woven fabric density detection device. The method comprises the following steps: forming a parallel transmission section by a to-be-detected fabric and an accompanying fabric and keeping a gap between the to-be-detected fabric and the accompanying fabric; projecting detection light to the parallel transmission section, and collecting a time-varying signal of light intensity penetrating through or reflected from the double-layer fabric; acquiring the movement speed of the to-be-detected fabric, and establishing a time corresponding relation with the light intensity signal; performing spectral analysis on the light intensity signal to extract a beat frequency signal; and calculating the weaving density of the to-be-detected fabric according to the frequency value and the movement speed of the beat frequency signal and the mapping relation between the frequency value and the movement speed. According to the scheme, the stable time domain beat frequency signal can be generated by utilizing the spatial heterodyne effect of the double-layer fabric, the spatial density information is converted into the time frequency information for measurement, the influence of motion blur and phase drift is effectively eliminated, the transmission or reflection detection mode is selected through adaptive judgment, the adaptability to different types of fabrics is improved, and the detection accuracy is improved. High-precision and high-stability weaving density on-line detection is realized.

The invention relates to the technical field of hovercars, in particular to a hovercar noise testing method and system. The method comprises the following steps: measuring hovercar noise and environmental background noise; the method comprises the following steps: acquiring acceleration direction and motion state data of an aerocar, establishing a mapping relation database of flight attitude and noise features, and inputting the extracted features into a hybrid classification architecture for working condition classification; the method comprises the following steps: carrying out noise separation, converting a time domain signal into a time-frequency domain signal, carrying out initial separation of a noise source by adopting an improved FastICA algorithm, carrying out space optimization by adopting an improved algorithm based on IVA, and carrying out feature refinement and classification based on a CNN-RNN hybrid model; different compensation methods are matched and selected according to time domain and frequency domain analysis results of environment background noise and hovercar noise; and performing spectral analysis and sound source localization on the separated noise source, and verifying a compensation effect. According to the technical scheme, the noise source of the hovercar can be dynamically measured and comprehensively analyzed.

The application relates to the technical field of wave energy utilization, and discloses a floating wave energy device and a narrow-slot resonance synergistic method and system of a floating breakwater. The method comprises the following steps: performing frequency spectrum analysis on a narrow-slot wave surface sequence to obtain a narrow-slot wave energy spectrum width parameter and a narrow-slot wave surface amplification factor, and generating a surface type switching instruction according to the comparison results of the two parameters with respective preset threshold values; triggering the rotation of a WEC floater around a vertical shaft according to the surface type switching instruction, interchanging a symmetrical section and an asymmetric triangular baffle section, converting transient hydrodynamic excitation generated in the rotation process into electric energy through a power output device, and obtaining a modal conversion benefit increment; combining the modal conversion benefit increment with the difference between the wave energy conversion efficiencies before and after switching, iteratively correcting the preset threshold value, and obtaining an updated surface type switching instruction generation rule. The application realizes the continuous collaborative optimization of the wave energy conversion efficiency and the wave dissipation performance under wide-frequency changing sea conditions.

The present application belongs to the technical field of oil and gas exploration, and particularly relates to a kind of exploration method of restricted tidal flat facies carbonate rock gas reservoir. Based on rock, logging data, seismic data, experimental test analysis data, through microfabric analysis, macro and micro combination approach, through rock fabric and mineral identification, restricted tidal flat facies rock development characteristics and regional scope are identified and defined; wherein the rock samples include pore development samples and samples with lithology of dark mudstone and argillaceous carbonate rock; frequency spectrum analysis method, weighted average method, organic matter mass balance method and coherent technology method are used to construct high-frequency sequence lithology-electricity interpretation model and multi-scale through-source fault transport pattern; thus, restricted tidal flat facies carbonate rock gas reservoir accumulation mode is obtained to explore restricted tidal flat facies carbonate rock gas reservoir. The present application innovatively explores restricted tidal flat facies carbonate rock gas reservoir, and solves the technical problems of identification and fine description of this type of gas reservoir.

The invention discloses a converter frequency coupling impedance test and calculation method and system. The method comprises the following steps: selecting a disturbance source form according to the type of a to-be-tested converter, and constructing an impedance test circuit of a steady-state working point; a steady-state working point of the converter is simulated by adjusting parameters of a controlled source for the impedance test circuit, and a positive-sequence harmonic disturbance signal and a negative-sequence harmonic disturbance signal are injected in a superposed manner, so that a response signal is obtained; performing spectral analysis on the positive-sequence harmonic disturbance signal, the negative-sequence harmonic disturbance signal and the response signal, and calculating phasors and phase differences of power frequency and harmonic components; based on the phase difference, performing phase correction on a coupling component in the response signal to obtain a correction result; and calculating equivalent harmonic impedance by using a correction result, and outputting a frequency coupling matrix of the harmonic impedance of the converter in the full frequency band. By implementing the method provided by the invention, the impedance measurement requirements of various converters are met, so that the limitations of unclear initial phase, lack of physical concept of coupling impedance, difficulty in four-quadrant impedance measurement and calculation and the like in the traditional technology are overcome.

This invention discloses a method and system for suppressing broadband oscillations in power systems based on improved virtual impedance. The method includes the following steps: acquiring grid-side and DC-side operating signals and converter output signals from the power system, and obtaining digital signals after preprocessing; performing spectral analysis on the digital signals to extract oscillation frequency characteristics, determining the current oscillation type in the power system, and outputting corresponding control signals; switching the operating mode of the filter in the dual-mode bandpass filter; outputting the corresponding oscillation component; matching and calling a pre-tuned virtual impedance parameter model, and generating virtual impedance amplitude and phase adjustment commands; converting the virtual impedance into a converter drive signal to regulate the converter output impedance characteristics and suppress broadband oscillations. This invention, through oscillation type identification and coordinated switching of two types of dual-mode filters, can regulate the converter output impedance without additional hardware, effectively suppressing broadband oscillations in the power system.