52 results about "Sinusoidal modulation" patented technology

The invention relates to microwave-free sensor technology with NV centers in diamond. In contrast to the prior art, the intensity of the pump radiation is not PWM-modulated, but monofrequency and sinusoidally modulated. Further measures, such as the use of semiconductor-based pump radiation sources and operation with an offset, prevent the formation of harmonics in the temporal intensity profile of the pump radiation irradiating the NV centers in the sensor element. This allows the sensor system to use the phase shift to determine measured values ​​of external physical parameters such as magnetic flux density, acceleration, temperature, etc., within a recognized and disclosed frequency range of the intensity modulation of the pump radiation, thereby minimizing the influence of noise from the pump radiation source. The galvanic isolation does not need to be compromised by cables from additional sensors.

The invention relates to the technical field of gas detection, and provides a doped gas concentration detection method and system based on a gas analyzer. The method comprises the following steps: constructing a standard spectrum database under the same pressure and temperature as a to-be-measured site; the method comprises the following steps: introducing sample gas into an optical absorption cell, carrying out wavelength scanning through a tunable diode laser in a plurality of adjacent absorption spectral line intervals containing target gas and interference gas, superposing a high-frequency sinusoidal modulation signal on a driving current, and synchronously detecting a second harmonic component of transmission laser to generate an actual measurement spectrum; fitting the actually measured spectrum with a synthetic spectrum generated on the basis of a standard spectrum database, and outputting a target gas concentration ratio as a detection result when a residual error meets a threshold value, so as to solve the technical problem that the detection precision is reduced due to spectrum overlapping caused by interference gas, and achieve the purpose that the detection precision is reduced by constructing the standard spectrum database and second harmonic spectrum fitting analysis. And the accuracy and the anti-interference capability of gas detection are improved.

The invention provides a welding method and device based on sinusoidal modulation Burst mode ultrafast Bessel light, and the welding method comprises the following steps: S1, a first workpiece to be welded is stacked above a second workpiece, optical contact is formed between the first workpiece and the second workpiece, and the first workpiece is made of a transparent material; s2, outputting ultrafast laser by a laser, and performing time and space shaping on the ultrafast laser to form ultrafast Bessel light in a sinusoidal modulation Burst mode; and S3, the light path is adjusted, ultrafast Bessel light in the sinusoidal modulation Burst mode acts on the target welding area, and welding of the transparent material is achieved. According to the method, ultrafast Bessel light in a sinusoidal modulation Burst mode is formed by conducting time and space shaping on ultrafast laser to act on a target welding area, the stable heating and melting process of a transparent material can be achieved, excessive heating of plasma can be greatly avoided, the ultrafast laser energy of an overall injection sample is reduced, and the welding quality of the transparent material is improved. And the welding strength and stability are improved.

The invention provides a permanent magnet frequency conversion double-sine modulation swimming pool pump energy-saving control method, and relates to the technical field of motor driving and control, and the method comprises the steps: building a double-sine carrier modulation model of a permanent magnet synchronous motor, and calculating a dynamic harmonic suppression factor and a double-sine modulation depth in real time; feedforward compensation is carried out on the inverter current based on the DHSIF, and a q-axis current reference value is generated by adopting double-closed-loop vector control; dynamically adjusting a carrier frequency range according to the DSMD, generating double sine carriers with a phase difference of pi / 3, and superposing the double sine carriers into a composite modulated wave; the modulation wave amplitude is corrected through a DHSIF, and fifth and seventh harmonics are eliminated in combination with an adaptive filtering algorithm; a carrier wave ratio is dynamically optimized to generate a PWM signal, and a transient compensation mechanism is triggered to correct a voltage instruction when a load suddenly changes; and an energy efficiency optimization database is constructed to call historical optimal parameters, and nonlinear mapping of DHSIF and motor characteristics is established through parameter self-tuning. According to the invention, cooperative control is realized through dynamic harmonic suppression, modulation depth optimization and intelligent thermal protection.

The invention relates to microwave-free sensor technology with NV centers in diamond. In contrast to the prior art, the intensity of the pump radiation is not PWM-modulated, but monofrequency and sinusoidally modulated. Further measures, such as the use of semiconductor-based pump radiation sources and operation with an offset, prevent the formation of harmonics in the temporal intensity profile of the pump radiation irradiating the NV centers in the sensor element. This allows the sensor system to use the phase shift to determine measured values ​​of external physical parameters such as magnetic flux density, acceleration, temperature, etc., within a recognized and disclosed frequency range of the intensity modulation of the pump radiation, thereby minimizing the influence of noise from the pump radiation source. The galvanic isolation does not need to be compromised by cables from additional sensors.

The invention discloses a three-phase three-wire three-level hybrid modulation switching method and device and a medium, and the method comprises the following steps: obtaining a three-phase sinusoidal modulation wave, and superposing a primary common-mode voltage to obtain a continuous first modulation wave; if the continuous space vector control is executed, comparing the first modulated wave with a carrier wave to form a first duty ratio signal; if the intermittent space vector control is executed, superposing the first modulation wave and a secondary common mode voltage based on a unified coefficient to obtain an intermittent second modulation wave; and according to a specific mode of intermittent space vector modulation, assigning a value to the unified coefficient to obtain a corresponding target intermittent space vector modulation wave. The device and the medium are both used for implementing the method. The method has the beneficial effects that the degree of freedom of the algorithm can be maximized through a PWM unification and coefficient modulation strategy; compared with a traditional mode, the complexity of an algorithm can be effectively reduced, and the reliability of overall code execution can be improved.

The invention discloses a single-stage multi-port converter DC side current ripple suppression method and device and a storage medium, and the method comprises the steps: obtaining an initial three-phase sinusoidal modulation wave according to the AC side three-phase voltage and current of a converter; obtaining a battery current control value according to the DC side photovoltaic voltage and current; obtaining an asymmetric carrier wave according to the DC side photovoltaic voltage and the energy storage battery voltage; according to the initial three-phase sinusoidal modulation wave and the asymmetric carrier wave, a battery current actual value is obtained, iteration is carried out according to an error between the actual value and a control value, and a zero-sequence component when the error is smaller than an error tolerance is obtained; injecting the zero-sequence component into the initial three-phase sinusoidal modulation wave to obtain an improved modulation wave; and intersecting the improved modulation wave with the asymmetric carrier wave to obtain a PWM driving signal of the converter. According to the invention, direct-current side current ripple suppression and power distribution between optical storage are realized through a zero-sequence component injection method, and the method has the characteristics of remarkable ripple suppression effect, low implementation cost and the like.

This application relates to a Rayleigh scattering noise suppression method and system for a distributed acoustic wave detection system. The method includes: performing optical phase sinusoidal modulation on a high-coherence continuous laser output from a narrow-linewidth laser in an FBG-based distributed acoustic detection system according to a set modulation scheme using an optical phase modulator; the set modulation scheme is Csin(2πf m t), C is the phase modulation amplitude, f m The phase modulation frequency and satisfying f m τ = k, where τ is the time difference between two adjacent reflected light pulses being detected, t is time, and k is an integer. A highly coherent continuous laser beam with sinusoidal phase modulation is passed through an unbalanced interferometer to generate dual light pulses. These dual light pulses are then injected into an FBG array for distributed acoustic wave detection. This achieves low-noise distributed acoustic wave detection and effectively improves the detection performance of FBG-based distributed acoustic wave detection.

The invention relates to the technical field of energy storage inverters, and discloses a three-port energy storage inverter and a control circuit and a control method thereof, and the method comprises the steps: achieving the flexible adjustment of an output voltage and an impedance mode through the design of a main circuit module and a control circuit module. The main circuit module can switch seven working modes to meet the requirements of different working conditions. The control circuit module uses a high-precision sensor, an advanced algorithm and a pulse width modulation technology to accurately control the output voltage waveform. The Hall sensor collects voltage and current, compares the voltage and current with sinusoidal modulation signals to generate error signals, outputs modulation signals after processing, drives the switching tube, and accurately controls voltage waveforms. The inverter improves the electric energy quality and dynamic regulation capability of renewable energy power generation, inhibits harmonic waves, improves the system stability and reliability, simplifies the multi-input port adaptation problem, reduces the system expansion complexity and cost, and has significant technical advantages and application prospects.

The invention discloses a force balance voltage modulation method of a Z-axis accelerometer, and belongs to the technical field of MEMS electrostatic driving. The Z-axis accelerometer comprises a mover mass block and a fixed type multifunctional multiplexing polar plate, a variable-spacing differential capacitor structure is formed, and displacement detection, driving force control and rigidity adjustment are achieved at the same time by multiplexing the structure. A PWM driving signal is generated through a dual PWM modulation method, sinusoidal modulation is carried out on the PWM driving signal and bias voltage together, a variable-spacing differential capacitor structure is used as a demodulator, a second-order mechanical vibration system is used as a low-pass filter, and a low-noise closed-loop driving torque is generated to stabilize the position of a mass block at a preset position. And meanwhile, low-noise direct-current static negative stiffness is generated, so that the system stiffness is reduced to a preset value. According to the invention, the variable-pitch differential capacitor structure can maintain the constant elastic coefficient of the system while generating the electrostatic driving torque, can provide sufficient control precision while reducing the leakage of driving signals, and can effectively suppress low-frequency noise.

The invention discloses a four-level discontinuous pulse width modulation method based on a variable reference carrier wave, which comprises the following steps: respectively injecting different zero sequence voltages into three-phase sinusoidal modulation waves to obtain a modulation signal 1, a modulation signal 2 and a modulation signal 3, the modulation signal 1 and the modulation signal 3 are obtained by injecting the same zero sequence voltage, and the modulation signal 1 and the modulation signal 3 are obtained by injecting the same zero sequence voltage; the values of different zero-sequence voltage coefficients are determined by the injected zero-sequence voltage signals; when the modulation signal 1 is larger than the carrier signal, the output state is the level P, otherwise, the output state is transited to the level O; when the modulation signal 3 is larger than the carrier signal, the output state is the level O, otherwise, the output state is transited to the level N; and when the modulation signal 2 is greater than the carrier signal, the output state is O2 level, otherwise, the output state is switched to O1 level. The neutral-point voltage balance control and switching loss optimization of the four-level NPC inverter are realized by injecting the optimized zero-sequence voltage component.

The application discloses a laser radar correction method and device based on an angular frequency field, a storage medium and electronic equipment, and the method comprises the following steps: controlling a laser radar to emit sinusoidal modulation light to irradiate a whiteboard, acquiring four-phase original intensity data and displacement increment values; reconstructing a phase sequence for each pixel and estimating an angular frequency, and forming an angular frequency distribution of a full field of view; establishing an analytical coupling model of the angular frequency and a rotation matrix according to the distribution, an internal parameter matrix and a whiteboard normal vector, solving a rotation matrix estimation value by using a least square method, and combining an initial normal distance to calculate a translation vector estimation value; calculating real distances of each pixel to a whiteboard point according to the rotation and translation estimation values, recalibrating phase zero point offset and fixed mode phase noise, and generating a correction lookup table; and outputting the rotation, translation parameters and the lookup table. According to the application, a pattern target is not needed, and only a whiteboard and a guide rail are used to restore external parameters, system errors introduced by tilting are reduced, and the ranging and point cloud reconstruction precision are improved.

The invention discloses a laser frequency stabilization electric control system based on a modulation transfer spectrum, and the system is constructed based on a ZYNQ7030 heterogeneous SoC platform, and integrates laser modulation, signal collection, error extraction, feedback control and man-machine interaction functions. Comprising a sinusoidal modulation chain driven by a high-speed DAC and an electro-optical modulator which are used for realizing laser frequency modulation; the MTS signal acquisition link consists of a photoelectric detector, a low-noise amplifier and a high-speed analog-to-digital converter; feedback control is carried out on the frequency of the laser through the precise digital-to-analog converter and the current source circuit. Meanwhile, the system integrates an air cavity temperature control module, a multi-channel communication interface and a man-machine interaction module, and frequency stabilization and system management are achieved. According to the invention, high-precision and high-stability laser frequency locking based on the rubidium atom absorption spectrum can be realized without depending on an external frequency standard, and reliable frequency reference is provided for applications such as high-precision atom physical experiments, quantum sensing, spectral measurement and the like.

The invention provides an edge light intensity adaptive laser scanning device and method based on a perturbation modulation strategy, and relates to the field of adaptive laser scanning devices. The edge light intensity adaptive laser scanning device based on the perturbation modulation strategy comprises a laser source used for generating a laser beam, a modulator connected with the laser source and used for modulating the laser beam according to the perturbation modulation strategy, a scanning mirror used for receiving the modulated laser beam and scanning the modulated laser beam to a target surface, and a light intensity detector used for detecting the light intensity of the laser beam. The method is used for monitoring light intensity of a target surface edge area in real time. According to the invention, through a perturbation modulation strategy combining sinusoidal modulation and random modulation, accurate control of the light intensity of the laser beam is realized, the modulator adopts an acousto-optic modulator, and the intensity and frequency of the laser beam can be flexibly adjusted in a sinusoidal frequency range of 1 kHz to 10 kHz and a random frequency range of 10 Hz to 1 kHz, so that periodic and random light intensity changes are generated, and the accuracy of the light intensity of the laser beam is improved. And the modulation effect is enhanced.

The invention discloses a speaker recognition model frequency modulation trigger injection method, particularly relates to the technical field of voice signal processing and artificial intelligence safety, and is used for solving the problems that an existing speaker recognition model back door injection method is insufficient in concealment, poor in black box environment adaptability, prone to distortion of trigger characteristics in the physical transmission process and poor in safety. And mainstream defense strategies such as model fine tuning, pruning and spectrum detection are difficult to resist. The method comprises the following steps: constructing a piecewise linear periodic low-frequency modulation curve for original voice, generating a smooth phase track according to a frequency and phase relationship, constructing a sinusoidal modulator to generate a hidden sample, mixing normal samples in proportion and uniformly marking, training a model by a black box, testing reproduction modulation and inputting the model; according to the method, the defects of insufficient concealment, black box adaptability, physical robustness and defensive resistance of an existing method are overcome, high-concealment, high-robustness and wide-application backdoor injection is realized, and reliable support is provided for security evaluation of a speaker recognition system.

The application provides a control method of a common ground type ten-switch voltage-doubled five-level single-phase photovoltaic inverter. Firstly, a single-phase sine modulation wave is compared with a four-phase laminated triangular carrier, and the voltage of a flying capacitor C2 is compared with a set reference voltage to obtain five preprocessed signals, then according to the conduction relationship of each switch tube among six working modes, the control signals of ten switch tubes are obtained through logical operation on the five preprocessed signals. The control method can stabilize the voltage of two flying capacitors, and the flying capacitors C1 and C2 can maintain stable voltage Upv during the whole working period, so that the waveform quality of the output voltage is ensured. In a word, the control method of the common ground type ten-switch voltage-doubled five-level single-phase photovoltaic inverter can not only stabilize the voltage of two flying capacitors, but also eliminate the leakage current and improve the utilization rate of the direct current voltage, and the five-level technology is used to reduce the generation of harmonic voltage.

The application belongs to the field of direct current transmission and relates to a sine modulation compensation method and system for a hybrid direct current energy consumption device, which comprises the following steps: obtaining an energy consumption valve sine modulation voltage according to surplus power of the hybrid direct current energy consumption device; if the energy consumption valve sine modulation voltage is negative, analyzing the cause of power imbalance of the energy consumption valve based on voltage non-negativity of a half-bridge energy consumption unit; and according to the cause of power imbalance of the device, expanding a compensation factor y through an alternating current component and reducing a compensation factor x through a direct current component, so as to ensure that the discharge energy and the charging energy of the energy consumption valve in a unit period are equivalent, and the average power of the energy consumption resistor in a unit period is equivalent to the surplus power. The method can effectively reduce the number of power devices of the hybrid direct current energy consumption device, greatly reduce the volume and cost of the hybrid direct current energy consumption device, and has great practical value and broad application prospect in the field of offshore wind power transmission through flexible direct current.

The invention discloses a mixing pulse width modulation method based on an elliptic vector model and an inverter system, and mainly relates to the technical field of mixing pulse width modulation inverters. Comprising the steps that a switching frequency generation model based on an elliptic vector model is established, and the switching frequency generation model is used for adjusting the switching frequency in real time according to the phase of sinusoidal modulation waves and completing frequency mixing modulation with controllable switching harmonic distribution frequency bands; performing discretization processing on the elliptic vector model by setting a harmonic discretization ratio and a carrier wave ratio to generate a sampling point phase sequence and a sampling period sequence in a sine period; according to the sampling period sequence, a pulse width modulation pulse sequence is generated through a natural sampling method and used for controlling on-off of an inverter switching device. The method has the beneficial effects that the problem of concentrated distribution of harmonic waves of the high-frequency switch is solved, the output efficiency of the converter is improved, and the purpose of enabling the output of the inverter to be more accurate, higher in quality and more efficient is achieved.

The invention discloses a gas detection method based on quantum cascade laser, and relates to the technical field of gas sensing. The method comprises the following steps: outputting laser triggered by a composite driving current by using a laser generator; the composite driving current is formed by superposing a high-frequency sinusoidal modulation waveform on a low-frequency scanning waveform; a quantum cascade laser is used for emitting laser, the laser passes through a multi-reflection pool after being collimated, gas to be detected is scanned, and a detector and a data acquisition card are used for synchronously acquiring light intensity scanning signals; in the processor, a time-division multiplexing algorithm and a compensation matrix are used for decoupling the light intensity scanning signal, corresponding gas and gas concentration are inverted and displayed in real time on a human-computer interaction interface, and when any gas concentration exceeds a corresponding preset threshold value, sound-light alarm is triggered, and an alarm signal is output to an administrator port. According to the invention, on the premise of not increasing the complexity of the system, the gas of which the absorption spectral line is very close to or even has cross interference can be accurately detected.

The application relates to a multi-stage motor initial position estimation method based on excitation signal sine modulation. An excitation voltage is taken as a carrier signal, and after being subjected to low-frequency sine modulation, the excitation voltage is applied to the stator winding of an exciter, and a three-phase low-frequency component is induced on the stator winding of a main motor to obtain a corresponding d-axis current. The d-axis current variance will reach a maximum value at a corresponding actual d-axis angle to obtain a rotor initial position theta 0_est1 , and the polarity of theta 0_est1 is identified according to the size of the d-axis transformed current before and after power-off. The method does not involve other complex filtering, phase-locked loop and other treatments, and thus has low requirements on the processor performance. Meanwhile, secondary identification of the magnetic pole is not needed. Finally, since a low-frequency signal is taken as a modulation wave, and a low-frequency induced signal is finally used as a data source for rotor initial position estimation, the attenuation of the low-frequency induced signal by the damping winding, the exciter winding and the main motor excitation winding is small, and thus the method has a high signal-to-noise ratio.

The present application relates to a control method, an inverter and a storage medium for a single-stage bidirectional high-frequency isolation inverter. The method includes: obtaining the voltage polarity of the secondary-side circuit and the power transmission direction of the inverter; determining the current working quadrant of the inverter based on the voltage polarity and the power transmission direction; determining a modulation strategy corresponding to the current working quadrant based on a sine modulation signal and a triangular wave signal; and controlling the working state of the switching tubes in the inverter based on the modulation strategy. By arranging a full-bridge module in the primary-side circuit and a chopper module in the secondary-side circuit, then determining the working quadrant of the inverter according to the voltage polarity of the secondary-side circuit and the power transmission direction of the inverter, and determining the corresponding modulation strategy according to the working quadrant to control the working state of the switching tubes in the inverter, so as to complete the normal operation of the inverter under non-unit power factor conditions.

This invention relates to a flux-modulated electric generator that utilizes a rotating Reluctance Modulation Cylinder (RMC) to dynamically modulate magnetic reluctance between a Magnetic Field Source (MFS) and a Power Extractor Assembly (PEA) by changing the reluctance of medium between PEA and MFS by sinusoidally. The RMC is constructed from chirped laminated ferromagnetic material on a non-magnetic conductive base and is driven by a small mechanical motor. As the RMC rotates, its varying thickness modulates the magnetic reluctance sinusoidally, creating a time-varying magnetic flux in the PEA. The PEA, composed of multiple electromagnets, captures this modulated flux and converts it into electrical energy through Faraday's Law of Induction. The MFS, which consists of permanent magnets or superconducting magnets, provides a stable and high-intensity magnetic field for flux modulation. The system is highly efficient due to the lightweight nature of the RMC, which significantly reduces mechanical power requirements compared to traditional generators with heavy rotating rotors. The generator also allows for individual load extraction through its series-connected electromagnets, making it adaptable to various power applications. This novel design offers enhanced efficiency, reduced mechanical wear, and versatility in power generation for both small and large-scale applications.

The invention relates to the technical field of power electronics, and discloses a multiplexing active clamping high-frequency link inverter secondary side modulation method, which comprises the following steps of comparing a reference sine modulation wave with a triangular carrier wave; the S1 and the S2 work in a complementary state with the frequency being the switching frequency fs and the duty ratio being (0.5-Td) / Ts. According to the secondary side modulation method for the multiplexing active clamping high-frequency chain inverter, the suppression effect on voltage ringing is not influenced while the soft switching characteristic is realized; the simulation waveform of the secondary side voltage of the transformer shows that the voltage ringing is suppressed near the steady-state voltage, so that the working stability and reliability of the inverter are ensured, and the damage of the high-voltage ringing to the device is avoided.

The invention discloses a method for simultaneously measuring the light absorptivity and the thermal diffusivity of an optical thin film based on phase-locked thermal imaging, which comprises the following steps of: focusing high-power laser subjected to light intensity sinusoidal modulation to form a point light source to excite an optical element, and forming a point heat source which is in same-frequency sinusoidal change along with time on the surface of the optical element through light absorption of the thin film; a same-frequency thermal radiation dynamic image signal emitted by the temperature rise of the sample is sampled and shot by the infrared CCD and is transmitted to the computer through the frame capturing device; a laser modulation signal is used as a reference signal, digital phase locking operation is carried out on discrete time domain signals of all pixel points of the CCD in different frames, and an amplitude image and a phase image can be extracted from noise; the numerical values of the light absorptivity and the thermal diffusivity of the optical thin film can be respectively obtained by analyzing the amplitude image data and the phase image data. The method can provide a non-contact, lossless, quantitative, rapid and online light absorption and thermal diffusion parameter quantitative measurement method for the intense laser optical film.

The present invention provides a method and system for extracting laser absorption spectrum by suppressing multiplicative noise. The system includes a test laser generation module, a non-absorbing laser generation module, an optical fiber coupler, an optical fiber splitter, an interferometer, a photodetector, a data acquisition module, an online compensation module and a computer. The test laser generated by the test laser generation module is split by a spectroscope. One beam is used by the interferometer to record the wavelength, and the other beam is combined with the sine-modulated laser generated by the non-absorbing laser generation module through the optical fiber coupler and then emitted by a collimating mirror. The combined beam passes through the gas to be measured and is detected by the photodetector. After being collected by the data acquisition module, the test laser and the non-absorbing laser are separated by the online compensation module, and the intensity change of the non-absorbing laser is used to compensate the intensity change of the test laser caused by the light deflection effect, so as to achieve accurate extraction of the absorption spectrum. The invention has a simple structure, can overcome the interference of the light deflection effect on the laser absorption spectrum, and has broad application prospects in the field of dynamic absorption spectrum testing such as combustion diagnosis.

The invention aims to provide a system and a method for generating a three-phase horn modulated wave from a three-phase sinusoidal modulated wave. The system comprises a three-path multiplier (1), an amplitude conversion module (2), a first summation module (3), a channel selection module (4), a second summation module (5) and a third summation module (6). The method comprises the following steps: a, generating an original sine wave signal by using a sine modulation wave generation system; b, performing equal amplitude transformation on the three-phase original sine wave signal by using an amplitude transformation module 2 to obtain a synthetic amplitude Uamp of the three-phase original signal; c, setting a proportionality coefficient Coe, and rectifying the original sine wave signal by using a multiplier (1); d, obtaining the content Ucom of the injected original signal by using a second summation module (5); and e, superposing the original sine wave signal and the content Ucom of the injected original signal obtained in the step d to obtain a horn modulation wave signal. The invention is applied to the technical field of power electronics.

The invention discloses a laser self-mixing interference rotating speed measurement method based on current modulation, and the method comprises the following steps: S1, building a light path, irradiating the laser emitted by a fixed-wavelength solid-state laser to a fixed measurement point of a measured rotating workpiece, and feeding back the light reflected by the workpiece in a diffuse manner into a laser cavity to form self-mixing interference; s2, laser current modulation: inputting a high-frequency sinusoidal modulation current with direct-current bias to the fixed-wavelength solid-state laser, and superposing a high-frequency modulation component in a self-mixing interference signal; s3, interference signal acquisition: a self-mixing interference signal containing a high-frequency modulation component is acquired and converted into a digital electric signal; and S4, signal demodulation and rotation speed calculation: processing the digital electric signal to extract stripe subdivision information, and calculating the instantaneous rotation speed of the workpiece. Compared with the prior art, the laser self-mixing interference rotating speed measuring device based on current modulation and the measuring method thereof have the advantages that high resolution and high signal-to-noise ratio are achieved.

The invention relates to the field of intelligent manufacturing, and discloses a binary sulfur hexafluoride decomposition gas detection method and device based on an infrared spectrum. The binary sulfur hexafluoride decomposed gas detection method based on the infrared spectrum comprises the following steps: modulating a direct current bias current based on a low-frequency linear scanning current and a high-frequency sinusoidal modulation current to obtain a direct current driving current, and inputting the direct current driving current into a laser generator to generate detection laser; receiving transmission laser after the detection laser passes through the decomposition gas to be detected; obtaining a transmissivity-time function of the decomposition gas to be detected according to the transmission laser and the detection laser; and determining a first detection result of the first target gas and a second detection result of the second target gas in the decomposition gas to be detected according to the transmissivity-time function. The binary sulfur hexafluoride decomposition gas detection method and device based on the infrared spectrum provided by the invention have the technical effect of realizing high precision of CO and CO2 gas in carbon-containing SF6 mixed gas.

The present invention discloses a system and method for achieving precise laser frequency stabilization. The system includes a laser, an atomic gas chamber, a photodetector, an A / D conversion module, a phase-locked amplifier, a DDS signal generator, a PID controller, and a D / A conversion module. The phase-locked amplifier performs phase-sensitive detection based on the detection signal and the sinusoidal signal generated by the DDS signal generator, and outputs two phase-sensitive detection signals to the frequency stabilization module. The frequency stabilization module adds the signal curves and searches for the zero point, obtains the voltage value of the frequency stabilization point and outputs it to the PID controller. The output signal of the PID controller is added to the sinusoidal modulation signal and output to the laser via the D / A conversion module to achieve frequency stabilization control of the laser generated by the laser. The present invention eliminates the frequency stabilization point deviation caused by the power change during the laser frequency sweep process, and solves the problem of error between the true voltage value of the laser frequency stabilization point and the found voltage value.

This invention discloses a method for identifying broadband voltage fluctuation types in power grids based on multi-feature fusion, relating to the field of voltage fluctuation technology. It addresses the problem of fluctuation type confusion under conditions of multiple disturbances and non-stationary operation. The method involves acquiring three-phase voltage data from voltage transformers and calculating the voltage deviation rate, while simultaneously retrieving the short-time flicker index. A fluctuation identification mechanism is jointly triggered based on these two factors. After triggering, a broadband voltage signal is acquired and modal decomposition is performed. The instantaneous frequencies of each mode are extracted and classified. Historical voltage data is retrieved to construct the voltage envelope trajectory, and the envelope asymmetry is calculated. Disturbances are introduced to different modes to enhance energy, and the modal energy spectra are calculated and fused to form modal modulation feature vectors. A pre-trained support vector machine model is used for classification mapping, achieving accurate identification of sinusoidal modulation, rectangular modulation, and interharmonic modulation voltage fluctuations, thus improving identification accuracy under complex operating conditions.