169 results about "Oscillation amplitude" patented technology

The invention provides a photovoltaic cell film thickness real-time monitoring method and system, and relates to the technical field of photovoltaic cells, and the method comprises the steps: setting a multi-channel optical fiber sensor array, enabling a receiving end optical fiber to collect a reflected light signal of a film, and enabling the reflected light signal to be connected into a photoelectric detector, and converting the reflected light signal into a reflected light intensity signal; preprocessing the obtained reflected light intensity signal, estimating the phase difference between adjacent cycles by using a phase unwrapping algorithm to obtain continuous thin film thickness change information, introducing a refractive index online estimation mechanism to compensate the refractive index change of the thin film material, and counting the oscillation amplitude in each cycle to obtain the refractive index of the thin film material. The real-time thickness value of the thin film is obtained in combination with compensation on the change of the refractive index; the thin film thickness distribution of the surface of the whole substrate is obtained through an intelligent interpolation algorithm, a thin film three-dimensional thickness distribution diagram is generated based on the obtained thin film thickness distribution through the graph drawing and rendering technology, and the dynamic evolution of the thin film growth process is presented in real time.

The invention belongs to the technical field of electroplating process optimization, and particularly discloses a titanium alloy surface electroplating control method which comprises the following steps: dynamically generating a hanger posture configuration scheme based on workpiece three-dimensional contour data acquired in real time; a bubble distribution image and electroplating liquid flow field data are synchronously collected, and a bubble-flow field coupling feature set is generated through multi-modal fusion; performing real-time linkage adjustment on the rotation speed and the swing amplitude of the workpiece according to the coupling feature set; after electroplating is completed, plating thickness, edge integrity and surface defect data are collected, and a multi-source plating data set is formed by combining workpiece position information; historical data and real-time data are integrated to carry out hanger layout adjustment judgment, and hanger spacing dynamic reconstruction optimization is started when adjustment is needed. According to the method, multi-parameter cooperative control and closed-loop quality optimization in the electroplating process are achieved, the uniformity and integrity of a titanium alloy workpiece coating are remarkably improved, and generation of bubble related defects is effectively restrained.

The invention provides a swing control method based on molten pool oscillation multi-feature fusion and related equipment, and relates to the technical field of welding, the method comprises the steps that in the argon arc welding process, an electric arc signal and a molten pool oscillation signal of a variable wall thickness welding area are collected in real time; oscillation amplitude, main frequency characteristics, current fluctuation coefficients and voltage-current phase difference characteristics are extracted from the molten pool oscillation signals and the electric arc signals and combined, and an oscillation comprehensive characteristic matrix is obtained; inputting the oscillation comprehensive characteristic matrix into a pre-trained classification model, and identifying a current molten pool state type; a corresponding swing compensation strategy is matched according to the state type of the molten pool, and asymmetric swing parameters are generated; and the asymmetric swing parameters and a preset basic welding track are subjected to superposition operation, and a composite control instruction is generated to control a welding gun to execute asymmetric swing welding. By implementing the method, different abnormal states of different molten pools can be subjected to differential control, and the stability of the variable-wall-thickness welding process and the forming quality of a final weld joint are improved.

The invention relates to the technical field of oscillation suppression, in particular to a control method and device for a subsynchronous oscillation suppression device, and the method comprises the following steps: collecting the frequency of a power grid, load fluctuation, the rotating speed of a generator and the excitation state of the generator, and recognizing subsynchronous oscillation frequency signals in a power system based on real-time operation state data; the subsynchronous oscillation frequency signal comprises oscillation frequency, oscillation amplitude and oscillation phase; analyzing the time-varying characteristics of the subsynchronous oscillation frequency signal through a time-varying analysis algorithm, wherein the time-varying characteristics comprise the time-varying characteristics of the oscillation frequency, the time-varying characteristics of the oscillation amplitude and the time-varying characteristics of the oscillation phase; the frequency suppression parameters are corrected according to the time-varying characteristics, and through an adaptive controller in the subsynchronous oscillation suppression device, based on the corrected frequency suppression parameters, real-time adjustment is carried out, a control effect is applied in real time, and subsynchronous oscillation is suppressed. According to the invention, the limitation of the traditional fixed frequency hypothesis is avoided, and the risk of misjudgment and insufficient suppression is greatly reduced.

The invention relates to the technical field of power grid deicing, and discloses a power grid deicing device and method based on environment detection and monitoring, and the device comprises a mounting part which sleeves an overhead cable between two power transmission line towers through a configured moving through cavity, so that the device can freely move in the direction of the overhead cable; therefore, monitoring and deicing operations at different positions are realized. The environment monitoring part judges whether icing occurs or not by acquiring environment information (such as temperature, humidity and wind speed) around the overhead cable, extracts character behavior characteristics in combination with image information, and further judges whether suspicious persons exist or not. And if it is judged that the overhead cable is iced, the mounting part can deice by oscillating the overhead cable, and the oscillation amplitude is automatically adjusted according to the environment information monitored in real time, so that the optimal deicing effect is achieved. According to the invention, the environment change can be intelligently monitored, the working strategy can be dynamically adjusted according to the real-time data, and the deicing efficiency and accuracy are improved.

An example system for passive sensing includes a coupled pair of resonators including a sensor resonator and a reader resonator, the sensor resonator including a resistor a loss associated with the resistor, and the reader resonator including a MOS cross-coupled pair that implements a nonlinear gain of the reader resonator via compressive saturation of negative resistance. An amplitude detector measures the amplitude of oscillations associated with the reader resonator, and the negative resistance is determined based on the measured amplitude of oscillations associated with the reader resonator when the measured amplitude reaches a steady state, i.e., when the gain of the reader resonator balances the loss of the sensor resonator. The resistance associated with the resistor of the sensor resonator may be determined based on the determined negative resistance. When the resistor is a resistive sensor, indications of measurements by the resistive sensor may be determined in this way.

The invention discloses a Hall thruster and a Hall thruster regulation and control method, and relates to the technical field of power devices, and the Hall thruster comprises a hollow cathode and a Hall accelerator. The hollow cathode is used for emitting electrons, the Hall accelerator comprises an anode, a first magnet exciting coil, a second magnet exciting coil, a discharge channel and a regulation coil, the first magnet exciting coil and the second magnet exciting coil are used for generating a first magnetic field, and the first magnetic field is at least distributed in a discharge area defined by the discharge channel; the anode is used for attracting electrons emitted by the hollow cathode into a magnetic field of a discharge area for ionization and generating discharge current, and under the condition that the oscillation amplitude of the discharge current is not lower than the target amplitude, the regulation and control coil is used for generating a second magnetic field which is used for adjusting magnetic field distribution in the discharge area. The oscillation amplitude of the discharge current is lower than the target amplitude, and the excitation power supplies of the excitation coil and the regulation coil are different. The Hall thruster has a good low-frequency oscillation suppression effect.

The invention relates to the technical field of power systems, and particularly provides a network construction type energy storage wide and low frequency disturbance suppression method suitable for a weak power grid environment. The method comprises the following steps: constructing an equivalent impedance model, and analyzing RLC resonance impedance matching conditions; constructing a quantitative model of impedance dynamic correlation; designing a multi-parameter adaptive virtual impedance module; constructing a cooperative control architecture of the adaptive virtual impedance and the network construction type energy storage converter; through verification of a continuous voltage drop simulation scene, adaptive adjustment parameters are optimized by adopting indexes of oscillation amplitude attenuation rate and stabilization time so as to ensure a wide and low frequency disturbance suppression effect under a weak power grid, and according to the method, broadband oscillation suppression under the continuous voltage drop scene is realized through adaptive virtual impedance, and dynamic accurate compensation is realized.

The invention relates to the field of aviation main pump detection, in particular to an aviation main pump verification test bed operation state monitoring method and system, and the method comprises the steps: obtaining the oscillation frequency, proportional gain, pressure change sequence and oscillation amplitude change sequence of an aviation main pump; a difference value between a preset target pressure value and a current pressure value is used as an adjusting pressure difference, an adjusting interval is equally divided and arranged according to the pressure adjusting direction, and the length of the pressure adjusting interval is corrected based on an oscillation amplitude change sequence; setting an initial proportional gain according to the length of the adjustment interval, taking the ratio of the number of pressure points in the adjustment interval to the response time of the adjustment interval as a pressure change rate, analyzing a positive or negative adjustment evaluation function according to the oscillation frequency and the pressure change rate, and constructing a proportional gain optimization model; and dynamic monitoring and adjustment of the proportional gain of pressure boosting and reducing of the aviation main pump are completed. According to the method, the accuracy of state monitoring is improved by optimizing adjustment interval division.

The invention provides a direct-current voltage synchronous control oscillation suppression method, system, equipment and medium based on transient dynamic energy dissipation, and belongs to the technical field of direct-current voltage synchronous control. A direct-current voltage synchronous control converter is equivalent to a synchronous machine model, a power angle dynamic equation based on a power grid angular velocity is established, and a damping coefficient is defined; adjusting a damping coefficient based on a differential relationship of the DC voltage deviation to control an energy dissipation rate; by adjusting the proportionality coefficient and the high-pass cut-off frequency, the voltage-angular velocity phase characteristic meets the oscillation suppression requirement, and angular velocity and voltage deviation reverse offset is achieved; a damping coefficient and compensation loop parameters are dynamically adjusted in real time according to DC voltage fluctuation and frequency deviation, an adaptive matching relation is established in combination with equivalent rotational inertia, and a phase compensation effect is maintained to suppress oscillation amplitude. According to the method, an oscillation mechanism is analyzed, and transient kinetic energy and transient potential energy are defined. Low-frequency oscillation is effectively suppressed, and the dynamic stability of the system is improved.

The invention relates to the technical field of data processing, in particular to a transformer fault monitoring method and system based on artificial intelligence. The method comprises the steps of collecting an input current data set and an output current data set, obtaining a characteristic deviation value of each datum in the input current data set, and obtaining a first oscillation amplitude of the input current data set based on the characteristic deviation value; acquiring a second oscillation amplitude of the input current data set, and acquiring a differential weight according to the first oscillation amplitude and the second oscillation amplitude; obtaining the load change of the power transformer according to the change consistency of the input current and the output current of the power transformer, and correcting the differential weight according to the load change to obtain a corrected differential weight; and inputting the corrected differential weight into a DE algorithm to optimize convolution kernel parameters of the CNN network, and then monitoring the fault of the power transformer, thereby improving the accuracy of transformer fault monitoring.

The present invention relates to the field of data processing technology, and in particular to a transformer fault monitoring method and system based on artificial intelligence. The method includes the steps of: collecting an input current data set and an output current data set, obtaining a characteristic deviation value of each data in the input current data set, and obtaining a first oscillation amplitude of the input current data set based on the characteristic deviation value; obtaining a second oscillation amplitude of the input current data set, and obtaining a differential weight according to the first oscillation amplitude and the second oscillation amplitude; obtaining a load change of the power transformer according to the consistency of the change of the input current and the output current of the power transformer, and correcting the differential weight according to the load change to obtain a corrected differential weight; inputting the corrected differential weight into the DE algorithm to optimize the convolution kernel parameters of the CNN network, and then monitoring the fault of the power transformer. The present invention improves the accuracy of transformer fault monitoring.

The invention relates to the technical field of laser processing control, in particular to a laser energy and light spot swing cooperative control method and system for laser welding, and aims to solve the problems that in the prior art, when parameters are linearly adjusted, the hysteresis effect of heat input and the nonlinear coupling relation of energy density are ignored; therefore, incomplete fusion, over-burning and non-uniform fusion depth of a welding seam are easily caused. The method comprises the following steps: acquiring a weld gap width estimation value and a gap change rate at the current moment; determining the target swing amplitude of the light spot at the current moment; calculating a laser power instruction value at the current moment; and a swing frequency instruction at the current moment is calculated, and closed-loop control is conducted on the welding process in cooperation with the laser power instruction value and the target swing amplitude. According to the method, no matter how the swing amplitude changes, the effective heat flux density acting on the unit area of the weld joint is kept constant, and therefore the consistency of the penetration depth is guaranteed.

The invention discloses a static var generator (SVG) additional dynamic damping-based broadband oscillation suppression method, which comprises the following steps of: acquiring three-phase voltage of an SVG machine end; according to the three-phase voltage, an oscillation frequency and an oscillation amplitude are obtained; performing band-pass filtering on the dq-axis voltage corresponding to the three-phase voltage according to the oscillation frequency; obtaining phase deviation introduced by band-pass filtering, and performing phase correction on the dq-axis voltage corresponding to the three-phase voltage; performing gain adjustment on the dq-axis voltage after phase correction to obtain a dq-axis current reference value under the oscillation frequency; and according to the dq-axis current reference value under the oscillation frequency, superposing the dq-axis current reference value with the dq-axis current reference value of the SVG to obtain a total reference value for controlling the dq-axis current. Positive damping in a wide frequency band of the power grid can be effectively enhanced, the impedance characteristic of the power grid is optimized, broadband oscillation of the system is suppressed, and the safety and stability of power grid operation are improved.

The invention provides a failure oscillation interval determination method, a temperature control method and related equipment, and the method comprises the steps: setting the width of a failure oscillation interval as the ith width at an ith test stage, obtaining the current chip temperature of a processor according to a preset period interval, and executing an error integral temperature control strategy to obtain a current frequency point corresponding to the current chip temperature, taking the current frequency point as an operation frequency point of the processor in the current period; monitoring whether the current chip temperature exceeds the target temperature or not in the ith test stage; if not, determining the target width of the failure oscillation interval according to the ith width, and further determining the lower limit of the failure oscillation interval. By formulating the failure oscillation interval when the error integral temperature control strategy is executed, when the chip temperature is in the failure oscillation interval, the updating of the integral error is stopped, so that the adjustment amplitude of the temperature is changed, the chip temperature is prevented from oscillating up and down near the target temperature, or the oscillation amplitude is reduced.

The invention discloses a device for realizing in-situ tuning of photo-induced dipole-dipole interaction between particles. The device comprises a light source module, a light trap modulation module, a vacuum cavity module, a detection module and a control module, the light source module provides reference light for the detection module while providing high-power laser for the light trap modulation module; the optical trap modulation module is used for modulating the laser beam to generate double beams with phase coherence; the vacuum cavity module provides a vacuum environment for the optical suspension nanoparticles; the detection module is used for detecting the movement of the nanoparticles; the control module is used for analyzing and processing the detection signal, inverting the interaction intensity of the particles, generating a control signal, controlling an intensity modulator in the light trap modulation module to apply alternating-current high-frequency modulation to a light beam, and realizing control on oscillation amplitudes of the two nanoparticles by utilizing feedback control; therefore, in-situ tuning and control of photo-induced dipole-dipole interaction among the nanoparticles are realized. According to the invention, stable suspension of double nanoparticles under high vacuum can be provided.

The invention provides an engine VVT clamping stagnation processing method and system, and the method comprises the steps: obtaining the static characteristics and dynamic response characteristics of an engine during operation, detecting the operation state of the engine VVT, and judging whether the VVT clamping stagnation exists or not; if VVT clamping stagnation does not exist, according to the set period, the oscillation amplitude and the oscillation frequency, a battery valve is driven to enable a VVT actuator to do reciprocating motion within the stroke range; if VVT clamping stagnation exists, a corresponding voltage compensation coefficient is obtained according to the real-time storage battery voltage, and oscillation is performed by adopting a strong oscillation mode or a limit position recovery mode based on the voltage compensation coefficient; and detecting the triggering times of oscillation, judging whether the VVT clamping stagnation is solved or not when the triggering times reach a triggering times threshold value, if so, entering PID control, and if not, judging that the VVT has a fault. By means of the method, VVT clamping stagnation can be prevented and repaired in the early stage, and the VVT fault rate and engine performance fluctuation are reduced.

The present application relates to the technical field of rail transit, and in particular to a wheel sensor and an axle counting system. The wheel sensor is used for detecting the rim of a train wheel and converting a detected signal from an analog signal to a digital signal, and the wheel sensor is laid on a rail; a junction box is arranged near each wheel sensor, junction boxes are in one-to-one correspondence with wheel sensors, and each junction box is connected to the adjacent junction boxes in front of and behind same; and all the junction boxes along the railway are cascaded and then connected to an axle counter host. The wheel sensor comprises: a linear feedback circuit used for feeding back the oscillation amplitude of an oscillation circuit in the wheel sensor in real time, and an excitation frequency adjusting circuit used for adjusting the oscillation circuit on the basis of the oscillation amplitude of the oscillation circuit, so as to adaptively control the oscillation amplitude of the oscillation circuit. The stable operation of the wheel sensor is ensured; cable laying costs can be reduced, the cable can transmit a sufficiently large amount of data, is not easily susceptible to interference, and has high reliability; and manufacturing costs are lowered.

A system (10) for emitting an acoustic signal in a frequency band between a lower threshold frequency and an upper threshold frequency, comprising a piezoelectric micromachined ultrasonic transducer (PMUT) (100) having a resonant frequency below the lower threshold frequency, a drive system (110) configured to apply a drive signal to the PMUT (100) so as to drive a membrane (103) of the PMUT (100) to oscillate, and a controller (120). The controller (120) is configured to control the drive system to drive the PMUT (100) at each of a succession of times, at a respective frequency of a succession of frequencies, starting with a first frequency below the lower threshold frequency. A frequency of the drive signal increases at each successive time, and an amplitude of oscillation of the membrane (103) increases at each successive time such that the resonant frequency of the PMUT (100) is caused to increase from an initial resonant frequency below the lower threshold frequency until it is above the lower threshold frequency. The PMUT (100) is subsequently driven at one or more frequencies within the frequency band so as to emit an acoustic signal within the frequency band.

The invention belongs to the field of integrated circuits, and particularly relates to a high-Q-value quick-start crystal oscillator based on an MLP neural network. A neural network is used for replacing a complex phase synchronization hardware circuit in a traditional energy injection technology. Firstly, working state parameters of a crystal oscillator are collected in real time through a state collection module; then mapping the received real-time digital information into a corresponding output instruction through a trained MLP neural network model, and further controlling an energy injection module to inject an energy signal in the same phase as crystal oscillation; along with gradual increase of the oscillation amplitude, when the oscillation amplitude reaches a threshold value, the MLP neural network control model outputs an injection stopping instruction, switches the switch state, and submits the instruction to the negative resistance oscillation circuit to maintain steady-state oscillation and output a stable oscillation signal. According to the invention, the low complexity and high robustness are taken into account while quick starting is realized, and a solution is provided for the application of the high-Q-value crystal oscillator in a low-delay and low-power-consumption scene.

The invention relates to an orthogonal time-frequency-space (OTFS) signal detection method based on message selective transmission, which is suitable for a high-speed mobile communication scene. According to the method, firstly, on the basis of an original MP detection algorithm, calculation of a symbol log-likelihood ratio (LLR) is added, the accuracy of message passing is improved, and by introducing an edge grouping strategy, edges with different channel coefficients are grouped to optimize a factor graph structure, and the influence of a loop effect on detection performance is reduced. And then a damping factor is introduced in the iteration process, the message oscillation amplitude in each round of iteration is controlled, and the algorithm convergence speed is increased. In the detection process, a damping message selective delivery (D-MsP) detector further improves the detection performance and convergence efficiency of the OTFS signal in the multipath channel by using a sparsity principle. The D-MsP detector realizes good balance between performance and computation complexity, computation overhead is remarkably reduced while high detection precision is guaranteed, and the method is particularly suitable for a high-speed mobile communication scene.

The invention discloses a virtual damping control method and system for a wind power grid-side converter, and the method comprises the steps: carrying out the high-precision tracking of an oscillation signal in q-axis current through a frequency phase-locked loop, extracting the oscillation amplitude and frequency in real time, taking the oscillation amplitude as the input of a P I controller, and dynamically calculating an optimal virtual resistance value. Through self-adaptive virtual damping control, the wind power grid-side converter can automatically adapt to complex working conditions such as power grid topology change and equipment switching, so that the grid connection stability of the wind power plant under the weak power grid condition is remarkably improved.

The invention discloses a broadband oscillation test system and test method for a converter, and relates to the technical field of electrical equipment testing, and the system comprises an equipment configuration and access module, a test mode switching module, a test operation and data acquisition module, a data automatic analysis module and a test report generation module. By constructing a closed hardware test loop, the comprehensiveness of the broadband oscillation test of the converter is improved, in a data analysis link, a broadband oscillation characteristic frequency identification formula is introduced, a time domain signal is converted into a frequency domain signal through fast Fourier transform, the broadband oscillation characteristic frequency is obtained, and meanwhile, through an oscillation amplitude normalization formula, the frequency domain signal is converted into the frequency domain signal to obtain the broadband oscillation characteristic frequency. According to the method, the oscillation amplitude after normalization is obtained, the dimensional difference under different working conditions is eliminated, in addition, a system impedance matching degree formula and a stability comprehensive evaluation index formula quantify the stability from the aspect of impedance matching and multi-parameter comprehensive evaluation, and the whole process from feature extraction to risk evaluation is covered.

The invention discloses a broadband oscillation active damping method, system and device based on MMC sub-module cluster collaboration and a storage medium, and relates to the technical field of power system stability control, and the method comprises the steps: collecting the electrical quantity of a power grid in real time, and recognizing a broadband oscillation mode and characteristic parameters through a signal processing algorithm; equivalent circuit parameters of the programmable virtual resonator are calculated, and the number of sub-modules of a sub-module cluster is determined in combination with the real-time states of the sub-modules of the modular multilevel converter; generating a control instruction according to the parameter and the oscillation component, and adjusting a sub-module pulse width modulation signal; oscillation amplitude attenuation, a damping ratio and a sub-module state are continuously monitored, adjustment is performed according to an evaluation result, and safe operation is ensured; the method can accurately suppress power grid oscillation, improves the utilization rate of the MMC device, saves the cost, is high in self-adaption, guarantees the reliable operation of the system, reduces the loss, is easy to expand and maintain due to the modular design, and improves the stability of the power system.

A microelectromechanical gyroscope device has: a detection structure, provided with a mobile mass; and an integrated electronic circuit, coupled to the detection structure and which provides a bias signal to the detection structure to cause its oscillation at a resonance frequency and acquires a detection signal from the detection structure indicative of a detected angular velocity. When the gyroscope device is powered, the integrated electronic circuit implements a start-up phase, following a previous power-down, wherein the mobile mass is biased to have an increase in the oscillation up to a target oscillation amplitude, followed by a maintenance phase at the target oscillation amplitude. The integrated electronic circuit is provided with a time counter stage for measuring a duration of a time interval from the previous power-down and adjusts the bias of the mobile mass during the start-up phase as a function of the measured duration of the time interval.

The invention discloses a surface sealing cone valve port structure design method for inhibiting cavitation surge, and belongs to the technical field of fluid transmission and control, and the method comprises the following steps: S1, obtaining the dominant frequency and amplitude of flow field oscillation caused by cavitation surge under different structure parameters according to simulation calculation; s2, calculating oscillation energy according to the dominant frequency and amplitude of the oscillation amplitude of the flow field, and analyzing the change relation between the cone angle of the valve port and the sealing length of the valve port and the oscillation energy; s3, calculating the optimal taper angle and sealing length of the valve port under different opening degrees according to the change relation between the taper angle of the valve port and the oscillation energy and the change relation between the sealing length of the valve port and the oscillation energy in combination with the change condition of the flow resistance of the valve port and the limitation that the length-diameter ratio of the valve port is larger than 2 and smaller than 4. According to the invention, the cone valve can achieve an excellent surge suppression effect within a certain structural range.

The invention discloses a power information dual-modulation method of an isolated DC-DC converter based on high-frequency harmonic amplitude modulation, and belongs to the technical field of power generation, power transformation or power distribution. The method is realized based on the design idea of complete separation of high-frequency carrier waves and fundamental wave frequency bands. The method comprises the following steps: firstly, modulating the waveform of an alternating current output voltage at a sending side, and performing ASK on a high-frequency harmonic wave carrying information to realize broadband information transmission and improve the channel capacity; the signal is amplified through the resonance network of the magnetic cavity, so that the signal-to-noise ratio is high, the detection is easy, and the quality of the output voltage is not influenced; and finally, information is demodulated by collecting the oscillation amplitude of the high-frequency alternating-current voltage at the receiving side. According to the method, each communication only needs one switching period, and the communication rate is improved compared with a traditional method; and flexible high-frequency signal amplitude modulation is supported, multi-system modulation is easy to realize, a plurality of bits can be transmitted in each communication, the output quality of direct-current voltage and the design of an isolation transformer are hardly influenced, and the integrity of power design is ensured.

The present invention can reduce phase noise while characteristics of an oscillation device are addressed.　This oscillation device comprises: a field effect transistor that outputs an oscillation signal through the drain thereof; and a control unit that controls the oscillation amplitude of the oscillation signal on the basis of the source potential of the field effect transistor. The field effect transistor may operate as a negative resistor of an LC oscillator. In the case in which the field effect transistor is an N-channel field effect transistor, the control unit may control the oscillation amplitude in a direction in which the lower limit value of the oscillation amplitude approaches the source potential of the N-channel field effect transistor.

To suppress an increase in power consumption during steady operation while preventing oscillation from stopping during the calibration of an LC oscillator. A calibration circuit includes a reference voltage generation unit, a voltage comparison unit, and an amplitude adjustment unit. The reference voltage generation unit generates a plurality of different reference voltages. The voltage comparison unit compares a detection value of an oscillation amplitude detected from an oscillation signal of the LC oscillator and the plurality of different reference voltages on the same polarity side of the oscillation amplitude. The amplitude adjustment unit adjusts the oscillation amplitude on the basis of a comparison result by the voltage comparison unit. The calibration circuit may include a frequency adjustment unit that adjusts an oscillation frequency of the LC oscillator.

The invention discloses a combustion instability feedforward control method and system based on modal early-stage identification, and belongs to the technical field of combustion control, and the method comprises the steps: S1, collecting a multi-physical field signal in a combustion chamber in real time; s2, based on the multi-physical field signal, identifying a current dominant mode and an amplitude increasing trend of combustion instability in real time; s3, double-condition judgment is carried out, and control is triggered before the oscillation amplitude reaches a preset safety threshold value; s4, matching a corresponding open-loop feedforward control strategy from a preset control strategy library; and S5, generating and applying a modal specific control instruction to drive an execution mechanism to perform intervention. According to the combustion instability feedforward control method and system based on modal early identification, early warning and modal specific control of combustion instability are achieved, the problems of phase mismatch and non-linear inadaptation are effectively avoided, the thermo-acoustic damage risk is remarkably reduced, and the reliability of the system is improved. And the robustness, the real-time performance and the engineering applicability of the control system are improved.