16 results about "Sinusoidal modulation" patented technology

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 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.

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 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.

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.

The invention discloses an energy-saving control method and device for a three-phase four-leg inverter and a storage medium, and belongs to the technical field of power electronics. The energy-saving control method comprises the following steps: acquiring a sinusoidal modulation input voltage signal of any phase and an output current signal of any phase of the three-phase four-leg inverter; determining a zero crossing point phase difference between the sinusoidal modulation input voltage signal and the output current signal; determining a common-mode voltage value according to the zero crossing point phase difference; according to the common-mode voltage value, correcting a sinusoidal modulation input voltage value of the sinusoidal modulation input voltage signal to obtain a sinusoidal modulation input voltage correction value; and determining a modulation input voltage signal of each phase of the three-phase four-leg inverter according to the sinusoidal modulation input voltage correction value. The energy-saving control method is used for reducing the circuit design cost.

The application discloses a photovoltaic grid-connected inverter system and a control method based on discontinuous modulation, and relates to the technical field of multilevel inverter control. The method comprises the following steps: obtaining a three-phase sinusoidal modulation wave of a multilevel inverter, constructing a square wave signal and adjusting the amplitude of the square wave signal, and dividing a clamping interval according to the intersection of the square wave and the three-phase sinusoidal modulation wave; based on midpoint balance and resonance suppression, the square wave signal is subjected to compensation voltage superposition; a control threshold for presetting the control midpoint voltage fluctuation range is determined, and the priority of controlling the midpoint voltage and suppressing common-mode resonance is determined; the square wave compensation voltage is adjusted according to the priority; the three-phase sinusoidal modulation wave and the square wave after the compensation voltage adjustment are compared, a DPWM common-mode modulation wave is determined, and a DPWM modulation wave is obtained, and the switching tube is controlled according to the DPWM modulation wave. The application can realize the multi-objective optimization control of midpoint voltage balance, common-mode resonance suppression and reduced switching loss.

The application discloses a single-stage multi-port converter DC side current ripple suppression method and device and a storage medium. The method comprises the following steps: obtaining an initial three-phase sinusoidal modulation wave according to three-phase voltage and current on the AC side of the converter; obtaining a battery current control value according to a DC side photovoltaic voltage and current; obtaining an asymmetric carrier according to the DC side photovoltaic voltage and an energy storage battery voltage; obtaining an actual battery current value according to the initial three-phase sinusoidal modulation wave and the asymmetric carrier, and performing iteration according to the error between the actual value and the control value to obtain a zero sequence component when the error is less than an error tolerance; 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 to obtain a converter PWM driving signal. The application realizes DC side current ripple suppression and power distribution between the photovoltaic and the energy storage battery through a zero sequence component injection method, and has the characteristics of remarkable ripple suppression effect and low implementation cost.

The application discloses a flicker measurement method based on feature reduction, and steps of the method comprise the following steps: extracting a power grid flicker envelope D(n) by using an improved Teager energy operator with two-point interval; analyzing and processing the obtained envelope D(n) by using a five-term Rife-Vincent window interpolation FFT method to obtain flicker modulation wave feature parameters: amplitude coefficient m i , frequency f i and initial phase angle θ i ; reducing the obtained feature parameters into a sinusoidal modulation signal, removing the amplitude coefficient m i from 4 / π and combining other parameters to reduce the sinusoidal modulation signal into a rectangular modulation signal; taking (1±10%) of the envelope signal D(n) as a threshold, comparing the number of data points of the reduced signal within the threshold, when the number of data points of one group is greater than N / 4, the greater one is the flicker modulation wave signal, and corresponding flicker parameters are output; if the number of data points of both groups is less than N / 4, no flicker occurs. The application provides a discrimination basis for flicker identification, overcomes the problem that a traditional flicker detection algorithm cannot effectively identify a flicker signal and is limited in use, and improves the detection precision of the flicker.

This invention discloses a zero-sequence component injection DPWM modulation method for driving a dual Y-shift 30° six-phase permanent magnet synchronous motor. The method involves superimposing a sinusoidal modulation wave with a zero-sequence component to form a 60° clamping discontinuous modulation wave. The steps include: S1: Obtaining the six-phase voltage modulation wave and its output current; S2: Taking three-phase windings with a 120° phase difference as one group and three-phase windings with a 30° electrical phase difference from the previous group as another group, obtaining the minimum absolute value of the voltage modulation wave and the maximum absolute value of the corresponding output current in each group; S3: Calculating the injected zero-sequence component in each group; S4: Superimposing the zero-sequence component onto the corresponding voltage modulation wave to obtain a DPWM modulation wave that adaptively clamps the maximum conduction current. This invention determines the optimal clamping region by detecting the inverter output current and reference voltage, reducing system switching losses. The zero-sequence component injection method avoids complex vector calculations, demonstrating significant application value.

The application discloses a lightning stroke imaging method based on piezoelectric array waveguide response, comprising the following steps: S1, arranging a sparse piezoelectric-waveguide array in a measured structure; S2, acquiring a lightning stroke waveguide response signal of the sparse piezoelectric-waveguide array; S3, filtering and processing the lightning stroke waveguide response signal through convolution of a sinusoidal modulation signal; and S4, pre-processing the lightning stroke waveguide response signal and implementing lightning stroke comprehensive imaging based on signal delay superposition. The lightning stroke imaging method based on piezoelectric array waveguide response is adopted, the lightning stroke waveguide response signal of the piezoelectric array is subjected to delay superposition for comprehensive imaging, online positioning monitoring of lightning stroke points is realized, and therefore high-precision imaging of lightning stroke events of large-area aviation composite material structures can be realized.

This invention discloses a single-stage self-equalizing IIOS converter for distributed photovoltaic MVDC aggregation. The invention comprises N sub-modules, each a three-port structure integrating interleaved parallel Boost units and hybrid full-bridge LLC resonant units. The former implements MPPT (Multi-Level Testing) for the distributed photovoltaic array, while the latter provides isolated voltage boost. Each sub-module's first port connects to an independent photovoltaic array, its second port is connected in parallel to a low-voltage DC bus, and its third port is connected in series to a medium-voltage DC bus. A control method is also provided based on this converter. By employing sinusoidal modulation with consistent primary and secondary drive logic, the hybrid full-bridge LLC resonant unit operates in DC transformer mode, with a constant sinusoidal resonant current. Furthermore, the second ports of each sub-module are directly connected in parallel, thus enabling self-equalizing output voltage among the sub-modules. This invention only requires sampling the output voltage and current of each distributed photovoltaic array to achieve MPPT for each sub-module and self-equalizing output voltage among sub-modules, eliminating the need for sampling the voltage at the third port or additional voltage equalization circuitry.

Disclosed in the present application are a dual-frequency control method for a power factor during grid connection of a flyback inverter, and a controller. The method comprises: acquiring an operating electrical signal of a power grid; obtaining a first sinusoidal modulation wave signal; obtaining a second sinusoidal modulation wave signal; on the basis of a power factor, determining a phase angle difference and a time difference corresponding to the phase angle difference; obtaining a sinusoidal correction modulation frequency; generating a sinusoidal correction modulation wave signal, the frequency of which is the sinusoidal correction modulation frequency; and by means of the sinusoidal correction modulation wave signal, controlling a flyback inverter to output an alternating current. The power factor is adjusted by means of adjusting the phase difference between a target power grid and a sinusoidal correction modulation wave; moreover, a first sinusoidal modulation wave can operate independently when a power source only has active power, and the sinusoidal correction modulation wave can operate independently when the power source requires reactive power adjustment. The flyback inverter is controlled by means of the sinusoidal correction modulation wave in the present application, such that the flyback inverter can accurately adjust the power factor during grid connection, and a harmonic distortion rate is reduced.

The invention relates to the technical field of voltage transformation, in particular to a high-frequency isolation type single-phase energy storage DC-AC conversion system, which generates different driving signals by comparing a power-frequency sinusoidal modulation wave with a high-frequency triangular carrier wave, controls a primary side full-bridge circuit and a secondary side chopper circuit to carry out voltage transformation, and improves the conversion efficiency. Therefore, the working frequency of the isolation transformer can be improved from power frequency to high frequency, the high-frequency transformer can be used for replacing a traditional power frequency transformer, output current and voltage closer to sine waves can be generated, magnetic loss and copper loss can be optimized, the size and weight of the high-frequency transformer are smaller, and cost is lower. The power density of DC-AC conversion is improved, and a multi-mode driving signal is generated through comparison of a power frequency sinusoidal modulation wave and a plurality of high-frequency triangular carriers, so that a target level generates more-mode changes, sine waves can be simulated more accurately, the waveform quality of output AC is improved, and waveform distortion of the output AC is avoided.

This invention relates to the field of cesium atom concentration detection technology, and particularly to a cesium atom concentration detection method based on TDLAS and 2f / 1f normalization. The technical solution includes the following steps: applying a composite modulation signal to a tunable semiconductor laser via a signal source, causing the laser output wavelength to periodically scan and modulate near the characteristic absorption spectral lines of cesium atoms; the composite modulation signal is composed of a low-frequency scanning signal and a high-frequency sinusoidal modulation signal superimposed; the modulated laser beam is incident on the cesium atom gas to be measured, generating a transmitted light signal carrying absorption information. This invention effectively eliminates common-mode interference such as light intensity fluctuations by independently and synchronously extracting harmonic signals using dual-locked-phase amplifiers and combining them with 2f / 1f normalization processing. It has advantages such as high detection accuracy, strong anti-interference capability, simple system structure, and ease of engineering implementation, and can meet the needs of online real-time monitoring of cesium atom concentration in complex environments.