1657 results about "Low-pass filter" patented technology

A tracking and adaptive compensation method for power fluctuation of a pulse load of a ship is provided. The method includes: based on a microgrid topology model of the ship, a pulse load model of the pulse load, and an interharmonic power and pulse parameter relationship model, performing power fluctuation tracking, frequency selection and a power spectrum analysis to obtain filtering parameters of a low-pass filter and filtering parameters of a band-pass filter; performing waveform adaptation to eliminate a phase delay caused by the low-pass filter and the band-pass filter, and obtaining a control command for a power compensation strategy; and generating, by a power loop, a pulse width modulation (PWM) signal to control a switching tube in a bidirectional direct current (DC) / DC converter of each of an energy storage battery pack and a supercapacitor of a hybrid energy storage system.

The invention relates to the technical field of power system stability control, in particular to a broadband oscillation suppression method and system for an offshore wind power flexible direct current grid-connected system and a medium, and the method comprises the steps: sequentially injecting positive and negative sequence perturbation sine harmonic signals at a grid-connected point of a wind turbine generator, constructing a multi-input multi-output impedance matrix, reducing the order of the multi-input and multi-output impedance matrix into single-input and single-output equivalent positive sequence impedance; the stability margin of the offshore wind power flexible direct current grid-connected system is obtained based on equivalent positive sequence impedance quantification; when the stability margin is lower than a preset margin threshold value, reconstructing the fan grid-side converter into a matrix control structure by cascading a weighting coefficient matrix between the inner and outer ring control loops of the fan grid-side converter; and iteratively optimizing the matrix type control structure based on impedance sensitivity, and synchronously connecting a low-pass filter in series in a voltage and current feedback channel to carry out impedance remodeling so as to finish broadband oscillation risk suppression. According to the invention, broadband oscillation suppression of the offshore wind power flexible direct current grid-connected system is realized through impedance modeling and a matrix type control strategy.

The invention discloses a high-precision current detection circuit calibration system, and belongs to the technical field of current detection circuit calibration. Comprising a shunt resistor, a Hall sensor array, a chopping amplifier, a low-noise operational amplifier, a temperature sensor, an ADC acquisition unit, an RC low-pass filter, a signal conditioning unit, a main control unit, an environmental parameter adaptive compensation module and a gain adaptive adjustment module. After an original signal is obtained from a multi-channel sensor, a dynamic error model is constructed in combination with temperature data, a long-term imbalance trend is extracted by using a moving average or median filtering algorithm, and real-time compensation is performed through a pre-calibrated temperature-drift function, so that the system maintenance period is remarkably prolonged.

The invention relates to the technical field of fault detection of the Internet of Things, in particular to a valve path detection method and system based on the Internet of Things, and the method comprises the following steps: based on real-time data of a valve path, removing high-frequency noise and high-frequency components in temperature fluctuation through a low-pass filter, carrying out the mean value smoothing operation of pressure data, and carrying out the mean value smoothing operation; and performing data standardization conversion on the flow data to obtain valve operation state data. According to the method, through real-time collection and optimization processing of valve operation data, it is ensured that the data is accurate and stable, weighted calculation is carried out in combination with the data influence degree, the representativeness of state feature extraction and the perception ability of working condition changes are enhanced, and based on state feature trend analysis, the sensitivity of fault detection is improved; and health state evaluation is carried out in combination with the operation duration and the load change, so that health state scoring is realized, the predictability of the long-term operation state is improved, false alarms and missing alarms are reduced, and the accuracy of fault early warning and the equipment health monitoring capability are enhanced.

The invention relates to a digital lock-in amplifier based on a frequency adaptive technology and a weak signal acquisition system and method, and the system comprises a front-end signal processing module which is used for obtaining a weak signal to be detected; the frequency self-adaptive tracking module is used for performing fast Fourier transform on the frequency of the weak signal to be measured to obtain the position of the maximum spectral line so as to synthesize a frequency control word, further generate a local reference signal and simultaneously adjust the coefficients of a low-pass filter and a loop filter and the series adjustment mode of a carrier synchronization ring; the multi-rate narrow-band low-pass filter module is used for multiplying the digital signal by a local reference signal and then carrying out filtering and down-sampling on a high-frequency signal to obtain a plurality of mutually orthogonal difference frequency components; the vector operation module is used for carrying out vector operation on the plurality of mutually orthogonal difference frequency components to obtain the phase and the amplitude in the weak signal to be measured; and the man-machine interaction module is used for displaying and storing the phase and the amplitude in the weak signal to be detected.

The invention discloses a linear polarization in-band scattering reconfigurable radiation time-sharing regulation array antenna, which belongs to the technical field of antenna engineering, and comprises an antenna unit and a one-to-sixteen power divider, the antenna unit is connected with the one-to-sixteen power divider, and the antenna unit is connected with the one-to-sixteen power divider. The antenna unit comprises a first radiation patch, a first dielectric substrate, a second radiation patch, a second dielectric substrate, a feed coupling branch knot, a feed metal column, a third dielectric substrate, a perforated metal floor and a fourth dielectric substrate, and a first PIN tube, a second PIN tube, a feed transmission line, a direct current bias device, a reflective phase shifter and a low-pass filter are arranged at the bottom of the fourth dielectric substrate; the direct-current bias device is connected with the reflection type phase shifter and the feed transmission line through the low-pass filter, and the feed metal column sequentially penetrates through the third dielectric substrate, the perforated metal floor and the fourth dielectric substrate and is connected with the feed transmission line. According to the invention, the normal radiation efficiency of the antenna can be ensured, and the reconfigurability of antenna scattering can be effectively improved.

The invention provides a power grid connection disturbance observer feedback control method, which belongs to the technical field of power grid connection, and comprises the following steps: detecting power grid impedance parameters by using a multi-frequency harmonic injection technology, designing a disturbance observer algorithm to establish a state equation set, and constructing a nominal inverter model by using a low-pass filter; the total disturbance amount is estimated in real time by comparing the difference value between the actual current output and the nominal model output, a feedback control strategy is constructed, the disturbance estimation value serves as a feedforward compensation signal to be superposed to the current controller output, and disturbance components in different frequency ranges are processed in a classified mode according to disturbance types. A disturbance observer bandwidth parameter and a filter cut-off frequency are set, a disturbance estimation value is compensated to a current control loop in real time through a feedforward compensation signal to suppress the influence of power grid disturbance on the grid-connected current, and the technical problem that it is difficult to accurately estimate and compensate the influence of power grid disturbance on the grid-connected inverter in real time is solved.

The invention relates to the technical field of image processing, and provides an image enhancement method and device and electronic equipment, and the method comprises the steps: carrying out the filtering processing of a to-be-enhanced image through employing a multi-scale low-pass filter with all-passband flat response, carrying out the dynamic range compression of the filtered image, and obtaining a multi-scale enhanced image; based on histogram distribution characteristics of the multi-scale enhanced image, dividing a pixel value range of the multi-scale enhanced image into a plurality of sub-intervals, and performing gray boundary truncation processing on each sub-interval to obtain a multi-scale interval image; dynamically determining a window size based on the scale feature of the multi-scale interval image, and performing multi-scale adaptive contrast limit histogram equalization on the multi-scale interval image based on the window size to obtain a multi-scale equalization image; and fusing the multi-scale equalized image to obtain a final enhanced image. According to the image enhancement method and device and the electronic equipment provided by the invention, the image enhancement effect is effectively improved.

The invention relates to the technical field of particle accelerators, in particular to a transverse feedback system with a switchable excitation direction and a control method thereof, and the system comprises a beam position detector BPM which is used for measuring a beam signal; the RF front end is used for receiving the beam signal sent by the beam position detector BPM and carrying out amplification and filtering processing; the ADC module is used for converting the beam signal into a digital signal; the digital signal processing module is used for carrying out digital signal processing calculation to obtain an excitation signal; the DAC module is used for carrying out digital-to-analog conversion; the power divider is used for adjusting the phase of the excitation signal; the exciter comprises four Kickers with electrodes, a power amplifier, a low-pass filter and a matched load and is used for applying a transverse excitation signal to the beam current, and the problems that in the prior art, a transverse feedback system Kicker occupies a large longitudinal space, the system is complex, and precision and efficiency are low are solved.

The invention discloses an image restoration method and device, a medium and equipment, and relates to the technical field of image processing. In order to solve the problem that useful information is lost in the transmission process of a deep network, an improved gating residual module is provided. Wherein the residual sub-module is embedded with a multi-scale frequency refining module which is provided for solving the problem that a fuzzy reconstructed image is caused by the fact that a traditional convolutional network suppresses high-frequency detail information, and the multi-scale frequency refining module dynamically obtains a low-pass filter from original input features through average pooling and feature folding operation; and low-frequency and high-frequency feature maps are separated through convolution operation, and spliced features rich in high-frequency information are obtained after weighting. According to the module, input features are down-sampled to three different scales through global average pooling operation, after the different scales are subjected to the same frequency refining operation, the features of each scale are restored into the input scale through a bilinear interpolation method, and after elements are added one by one, output features are obtained.

The invention relates to the field of electric power, and discloses an electric energy metering method, system and device and a storage medium, and the method comprises the steps: employing an FIR zero compensation angle difference algorithm to correct a synchronization error angle difference between a current signal and a voltage signal, employing a self-convolution cascade zero-pole low-pass filter algorithm to carry out the filtering processing of a synchronization current signal and a synchronization voltage signal, and obtaining a current signal and a voltage signal; correcting a real-time phase difference between the filtering current signal and the filtering voltage signal by adopting a high-real-time FIR zero-step angular difference algorithm to obtain a corrected current signal and a corrected voltage signal, sampling to obtain current data and voltage data, and obtaining an initial electric energy metering result according to the current data and the voltage data; and obtaining environmental factors, calling a pre-trained electric energy metering error prediction model to obtain an electric energy metering prediction error, and obtaining a final electric energy metering result according to the initial electric energy metering result and the electric energy metering prediction error. The electric energy metering method with high accuracy and high linearity is provided, and the problem that an existing electric energy metering mode is large in measurement error is solved.

The invention discloses a method for improving the stability of a system for sending out deep and far sea wind through a dual-port light converter. The method comprises the following steps: introducing a voltage feed-forward path comprising a phase compensator and a low-pass filter into an MMC differential mode control loop in the dual-port light converter; and a compensator parameter feasible region is calculated based on the phase characteristics of the oscillation risk frequency band, and the cut-off frequency of the filter is set, so that targeted phase compensation and impedance remodeling are realized, and the damping of the dual-port light converter is effectively enhanced. According to the method, the impedance characteristic of the dual-port light-weight current converter in the oscillation risk frequency band is remarkably improved, and a reliable technical path is provided for improving the stability of the dual-port light-weight current converter.

The present invention relates to the fields of PID control and Kalman filtering, and disclosed is an improved PID control method based on Kalman filtering. The present invention comprises: in the process of acquiring a target value of an expected signal, taking the difference between the target value and a current feedback quantity of a controlled object to obtain an error value, acquiring an output of PID from the error value, applying the output of PID to the controlled object to obtain a noisy output signal, then, after Kalman filtering, feeding the output back to PID, continuously iterating to make the feedback quantity approach the target value, and finally obtaining a stable output signal. Variable-speed integration and integral separation algorithms are added to an integral term of PID to change an integration speed on the basis of a system deviation, and an incomplete differential algorithm and a low-pass filter are added to a differential term of PID to prevent high-frequency interference. According to the present invention, the optimal estimation of a system state is obtained by means of prediction of a current state and updating of observation data, thereby reducing the influence of measurement errors and noise, and improving the performance and stability of a PID controller.

The embodiment of the invention provides an excitation signal generation method and system and a digital eddy current sensor, and the method comprises the steps: outputting a square wave signal through a pulse width modulation assembly of a microcontroller unit, and enabling the frequency and resolution of the square wave signal to be adaptive to eddy current probes with different inductance values; inputting the square wave signal into a low-pass filter for filtering, and setting the cut-off frequency of the low-pass filter, the suppression times of higher harmonics and the attenuation slope so as to output a sine wave signal with a target total harmonic distortion range; the amplitude of the sine wave signal is collected in real time, and the pulse width modulation duty ratio and the passband gain of a low-pass filter are dynamically adjusted in combination with a digital control algorithm, so that the sine wave signal is subjected to self-adaptive adjustment and correction and is output; and taking the sine wave signal as an excitation source of an eddy current probe, and driving the eddy current probe to carry out nondestructive testing. According to the invention, the excitation signal which gives consideration to high-frequency signal generation, deep harmonic suppression and digital adaptive adjustment can be generated.

The invention discloses an active damping control system for improving the output impedance of a current source type inverter, which comprises a current loop control loop, an active damping branch and an improved phase-locked loop, and is characterized in that the difference value of reference current and feedback network access current passes through a current controller to form the current loop control loop; the voltage of the grid-side inductor is fed back to the output of the current loop through the virtual resistor link to form a damping branch, and the voltage of the common coupling point enters the traditional phase-locked loop link through the low-pass filter and forms an improved phase-locked loop through phase compensation. The optimal feedback coefficient of the damping branch is designed according to the optimal damping ratio, the low-pass filter parameters are designed according to the phase at the maximum resonant frequency, the reasonable proportional gain link is designed according to the improvement of the output impedance amplitude, the resonance of the current source type inverter can be effectively inhibited, the output impedance of the inverter is increased, and the output impedance of the inverter is improved. And the quality of the network access current of the current source type inverter and the stability margin of the current source type inverter in a weak power grid are improved, and the stability of the system is improved.

The invention discloses an InSAR (Interferometric Synthetic Aperture Radar) phase filtering method based on a plurality of interferograms, which comprises the following steps of: preprocessing acquired main and auxiliary SAR images to obtain the plurality of InSAR interferograms; dividing the plurality of InSAR interferograms into square interferogram patches along the azimuth direction and the distance direction; converting each interferogram patch from a spatial domain into a frequency domain signal, and constructing a corresponding frequency spectrum amplitude diagram; using a K-means clustering method to cluster and extract an initial low-pass filter in the spectrum amplitude diagram, and constructing a phase filter together with a Kaiser window function; the frequency domain signals of the interferogram plaques pass through a phase filter, the signal frequency band power is reserved, the noise at the high-frequency position is filtered out, meanwhile, the noise at the low-frequency position is filtered out through smoothing operation, and the filtered frequency domain signals are obtained; and the filtered frequency domain signals are converted to a spatial domain, filtered interferogram patches are obtained and spliced, and a filtered InSAR interferogram is obtained. The method is beneficial to popularization and promotion of the development of the current time sequence InSAR interferometry technology and the application in engineering.

The invention provides a radio frequency front end module. The circuit comprises a first matching circuit, a first-stage power amplification circuit, a coupler, a first radio frequency switch, a radio frequency main path, an attenuation path, a second radio frequency switch, a second matching circuit, a second-stage power amplification circuit, a third matching circuit, a power detection circuit, a low-pass filter, a first operational amplifier and a hysteresis comparator. The hysteresis comparator is used for controlling the input end of the first radio frequency switch to be communicated with the first output end of the first radio frequency switch or the second output end of the first radio frequency switch; and meanwhile, the control circuit is used for controlling the first input end of the second radio frequency switch or the second input end of the second radio frequency switch to be communicated with the output end of the second radio frequency switch. According to the radio frequency front-end module, on the premise that the power amplification circuit is not damaged, normal output of the radio frequency signal can be ensured, and meanwhile the situation that a post-stage output signal is distorted due to reduction of the bias voltage is avoided.

The invention discloses a fuel cell hybrid train energy dispatching method and system. The method comprises the steps that S1, a hydrogen fuel hybrid train power system model is constructed; s2, acquiring required power in a train running process, and decomposing the required power into a low-frequency component and a high-frequency component by using a low-pass filter with adjustable cut-off frequency; constructing a double-layer reinforcement learning agent, and performing real-time dynamic optimization adjustment by taking the cut-off frequency of the low-pass filter as an action variable of the reinforcement learning agent; s3, designing a multi-objective reward function and a system total cost function, and synchronously optimizing fuel cell efficiency, fuel cell power fluctuation, hydrogen consumption and lithium battery SOC to approach initial values; and updating double-layer reinforcement learning agent network parameters through a depth deterministic strategy gradient algorithm, and finally outputting a real-time power distribution instruction of the fuel cell and the lithium battery. The method has the advantages of reducing the fluctuation of the output power of the hydrogen fuel cell, reducing the hydrogen consumption and the like.

The invention provides a fan rotor kinetic energy control power optimization method based on variable parameter Kalman filtering, and belongs to the technical field of wind power generation. The technical problem of phase delay existing in smoothing of a traditional low-pass filter is solved. According to the technical scheme, the method comprises the following steps: S1, designing a Kalman filter equation for a wind turbine generator, and smoothing an output power reference value of the wind turbine generator; s2, wind turbine generator rotor kinetic energy state variables are introduced, and wind turbine generator rotor kinetic energy is subjected to optimization control; s3, designing fuzzy control considering the wind turbine generator rotor kinetic energy demand quantity and the wind turbine generator rotor kinetic energy state variable; and S4, reference smooth power is obtained through variable parameter Kalman filtering, a reference rotating speed is obtained through wind turbine generator rotor kinetic energy control, and stabilization of the output power of the wind turbine generator is achieved. According to the invention, smoothing processing can be carried out on the output electromagnetic power at the turbulent wind speed.

The invention discloses a moving-coil geophone zero-phase corrector based on a state variable shaper. The zero-phase corrector comprises a state variable shaper, a differential-to-single-ended module and a single-ended-to-differential module. After a moving-coil geophone signal is input into a differential signal, the signal is converted into a single-ended signal suitable for filtering through the differential-to-single-ended module, and a high-pass filter, a band-pass filter and a low-pass filter in the state variable shaper correct the phase characteristic of the frequency response of the geophone to a zero-phase attribute. And finally, the single-ended to differential module converts the single-ended signal into a differential signal again and outputs the differential signal. The phase characteristic correction method can be used for phase characteristic correction of differential signals of the moving-coil geophone, low-frequency response can be expanded while the phase is corrected by changing resistance value adjustment, gain stability in the original bandwidth is kept, phase characteristic correction is provided for output of the moving-coil geophone with different frequencies and amplitudes, and the correction precision of the moving-coil geophone is improved. And the accuracy of the detector signal phase is improved.

The embodiment of the invention provides an assisting power output control method of an electric bicycle, the electric bicycle and a storage medium, and the method comprises the steps that the current motor rotating speed of the electric bicycle and the current torque value applied to pedals of the electric bicycle are collected; adjusting the cut-off frequency of a first low-pass filter based on the current motor rotating speed, and filtering the current motor rotating speed through the adjusted first low-pass filter to obtain a smooth rotating speed; determining a motor torque compensation value based on the motor rotating speed fluctuation quantity between the smooth rotating speed and the current motor rotating speed; and determining a motor torque output value based on the motor torque compensation value and the current torque value, and controlling the power output of the electric bicycle according to the motor torque output value. By means of the power assisting device, the technical problem that power assisting output of the electric bicycle is not smooth due to mechanical shaking or resonance is solved.

The invention belongs to the technical field of optoelectronic devices, and provides a laser gyroscope frequency stabilization system and a frequency stabilization method thereof.The laser gyroscope frequency stabilization system comprises a large laser gyroscope to be subjected to frequency stabilization, an electro-optical modulator, an adjusting light path, a signal generator, a mode matching mirror set, a PID regulator, a frequency mixer, a photoelectric detector, an ultra-stable cavity, a low-pass filter, a computer and a data acquisition card; and a square transmission light path is arranged in the ultra-stable cavity. According to the invention, the problem of insufficient isolation caused by an optical isolator consisting of a polarization splitting prism and a 1 / 4 wave plate is effectively avoided, the influence of an optical feedback effect is reduced, and the optical isolator is better adapted to the field of high-precision measurement related to a large laser gyroscope.

A material complex dielectric constant measuring system belongs to the technical field of microwave dielectric measurement and comprises a self-harmonic oscillator, a phase-locked loop and an envelope detector. The self-harmonic oscillator comprises a resonator, a first radio frequency amplifier and a first power divider; two ends of the resonator are respectively connected with the output end of the first radio frequency amplifier and the input end of the first power divider; the phase-locked loop comprises a mixer, a low-pass filter and a voltage-controlled oscillator. The phase-locked loop and the envelope detector are used for demodulating signals and mapping signal frequency and power to direct-current voltage, the voltmeter is used for measuring phase-locked loop control voltage and envelope detector output voltage, and the relation between the size of the complex dielectric constant of the material and the voltage is obtained. The phase-locked loop control voltage can be measured from the voltage control end of the voltage-controlled oscillator. The system is simple in structure, small in size, easy to carry and suitable for field rapid measurement and mobile application, the measurement result is more comprehensive, and the system has higher measurement precision and stability.

The invention discloses a specific grid-connected current harmonic suppression method and device for an energy storage converter, and belongs to the technical field of power systems, and the method comprises the steps: obtaining a given current value of a fundamental current loop, and carrying out the dq / abc conversion to obtain a three-phase current reference value; acquiring a three-phase current value of a power grid side, and subtracting the three-phase current value from the three-phase current reference value to obtain a harmonic current value; converting the harmonic current value to a target subharmonic synchronous rotating coordinate system to obtain a target subharmonic current value; extracting the target sub-harmonic current value in a direct current form through a low-pass filter, and sending the target sub-harmonic current value to a PI regulator for regulation to obtain a harmonic voltage compensation amount; and injecting the harmonic voltage compensation amount into a modulation wave to realize suppression of the target subharmonic current. According to the invention, the grid-connected side current harmonic of the energy storage converter can be effectively suppressed, and the grid-side current quality is improved.

Methods and apparatus for filtering a signal using a current mode filter circuit that enables source degradation. An example filter circuit generally includes an input node; an output node; a power supply node; a first transistor including a drain coupled with the input node; a second transistor including a drain coupled with the output node and including a gate coupled with a gate of the first transistor; a capacitive element coupled between a drain of the first transistor and the power supply node; a first resistive element coupled between the drain electrode and the gate electrode of the first transistor; a first source degeneration element coupled between a source of the first transistor and the power supply node; and a second source degeneration element coupled between a source of the second transistor and the power supply node.

A modular and scalable AC / DC substation transforms AC voltage to DC voltage for driving a high-voltage and high-current load, such as a heavy work machine. Sized to fit within a standard high-cube ISO shipping container, the substation includes a main transformer attached at a center of a rectangular base with a pair of controlled rectifiers positioned on the base downstream from the main transformer, aligned parallel to a lateral axis of the base, and substantially symmetrical to a longitudinal axis of the base. The arrangement of these components on the base, together with lowpass filters and switchgear, achieves high power density for the substation, provides balanced mass for stability during shipment and placement, and helps protect personnel from accidental electrical arcing.

The invention discloses a composite impedance remolding stability improving method based on power grid voltage feedforward, and the method comprises the steps: connecting a low-pass filter in series in a power grid voltage proportion feedforward link, maintaining the power grid voltage feedforward low-frequency harmonic suppression capability, and improving the phase margin of the output impedance of an inverter in a middle-high frequency band at the same time. And a power grid voltage feed-forward branch for eliminating the negative damping influence of the phase-locked loop is added to a public grid-connected point, so that the stability of the grid-connected inverter is improved, the phase margin of the system is greatly improved, and the grid-connected inverter can still keep higher robust stability when the impedance of the power grid is higher. The stability of the grid-connected inverter is improved when the impedance of the power grid changes in a wide range, the quality of grid-connected current is improved, and the problem that the system is faced with instability after the influence of power grid voltage feedforward and PLL is considered under a weak power grid is effectively solved.

The invention discloses a dynamic frequency adaptive automatic gain control system, which belongs to the field of dynamic frequency adjustment and comprises a radio frequency power amplifier, an attenuator, a logarithmic detector, a low-pass filter and a comparison and control signal generation module. The amplified radio frequency signal is input into the attenuator; the attenuator attenuates the signal so that the input radio frequency signal reaches a range suitable for detection of the logarithmic detector after attenuation; the logarithmic detector converts the radio-frequency signal into a direct-current voltage proportional to the signal power; voltage signals of direct-current voltage output by the logarithmic detector are smoothed through a low-pass filter, and rapidly changing components are removed; and the comparison and control signal generation module compares the smoothed voltage with a reference voltage, generates a control signal for adjusting the gain, and adjusts the gain. According to the invention, instant gain adjustment is provided under the condition of rapidly changing signals, and the energy efficiency of the system is improved.

Provided are: a glass member that excels in tactile sensation such as the feel of writing and the feel of touch; a glass member laminate; an input device; an input display device; a glass member for exterior use; a housing; a door body; a container; and a method for manufacturing the glass member. In first irregularities, the arithmetic mean height Sa1 is 2-500 nm and the mean width RSm1 of roughness profile elements is 2-100 μm when it is assumed that the cutoff value of a high-pass filter λc1 is 14 μm and the cutoff value of a low-pass filter λs1 is 0.35 μm. In second irregularities, the arithmetical mean height Sa2 in a square region with one side measuring 5 μm is 0.7-50 nm when it is assumed that the cutoff value of a high-pass filter λc2 is 2.5 μm.

The invention discloses a control method and device for improving broadband oscillation stability of a grid-forming type converter, solves the problem that the grid-forming type converter generates intermediate frequency oscillation after a virtual inductor is introduced, and belongs to the technical field of power electronic grid-connected equipment control. The method comprises the steps that virtual synchronous control is adopted by a grid-forming converter, a VSG reference voltage amplitude is obtained according to an active and reactive control loop, and a converter output voltage reference value is obtained by combining an alternating current voltage and current double closed loop of a virtual inductor, a current value of a grid-connected line is sampled, and a dq-axis component of grid-connected current under a rotating coordinate system is obtained; a differential item obtained after the dq-axis component of the grid-connected current in the rotating coordinate system is multiplied by the virtual inductance passes through a first-order low-pass filter, a dynamic virtual inductance item of the dq axis in the rotating coordinate system is obtained, the dynamic virtual inductance item is introduced into an alternating-current voltage loop input end in an alternating-current voltage and current double closed loop, and the broadband oscillation stability of the grid-forming type converter is improved.