95 results about "Harmonic filtering" patented technology

The invention provides a weak signal multi-module networking self-adaptive monitoring system for power transmission and transformation construction, and relates to the technical field of multi-module networking, and the system comprises a multi-mode module which is used for deploying a multi-mode sensing unit at a key monitoring point of power transmission and transformation equipment, collecting vibration, partial discharge, leakage current and environmental parameter signals, and transmitting the signals to a monitoring center; the signals are processed through packaging of an electromagnetic shielding shell and a built-in harmonic filter circuit so as to obtain original monitoring signal data; and the detection module is used for inputting the original monitoring signal data into the chaotic enhanced weak signal detection device, and extracting a fault feature vector by capturing an attractor phase diagram abrupt change and a time domain waveform threshold. Through the multi-mode sensing and self-adaptive networking technology, monitoring of power transmission and transformation weak signals and timely extraction of fault features are achieved, and the fault early warning accuracy and the self-adaptive capacity are improved.

The invention provides a split type direct current charging multi-split group charging and group control control system, and belongs to the technical field of split type direct current charging piles. The split type direct current charging system comprising a main control cabinet, a power distribution unit, a charging pile terminal and other hardware architectures is constructed; a voltage monitoring unit, a current sensor module, a harmonic filter and other multi-dimensional sensor networks are integrated to acquire power grid state data in real time, and a sliding time window method is used to carry out segmented analysis on the data to extract power grid characteristic parameters; establishing a multi-objective optimization model comprising a power balance equation and a power grid stability equation to calculate an optimal power distribution matrix, adopting a neural network to realize intelligent distribution and dynamic balance adjustment of the power of each charging pile terminal, and starting an emergency power redistribution mechanism to ensure stable operation of the system when the power grid is detected to be abnormal. The technical problem of unbalanced power distribution of the multi-pile charging system caused by power grid voltage fluctuation and harmonic pollution is solved.

The invention relates to a radial frequency-doubled sound filtering metamaterial and a topological optimization design method thereof.The radial frequency-doubled sound filtering metamaterial comprises scatterers which are arranged on a base body and distributed in a concentric circle mode, and the topological optimization design method comprises the following steps that a two-dimensional axial symmetry model is established, the two-dimensional axisymmetric model corresponds to the cross section of the radial frequency-doubled sound filtering metamaterial in the radius direction and comprises periodically arranged unit structures, and each unit structure comprises a main board and a square design domain; a Floquet periodic boundary condition is applied to parallel boundaries of a unit structure in the radius direction, other boundaries are set as free boundaries, a genetic algorithm is adopted to carry out iterative optimization on the material distribution topology of a square design domain, the optimal material distribution topology of the square design domain is obtained, and then the final optimized shape of the radial double-frequency sound filtering metamaterial is obtained. Compared with the prior art, the invention has the advantages of capability of realizing omni-directional sound wave frequency doubling filtering, high design reliability and the like.

A voltage synchronizing signal detection method based on an improved DSOGI-PLL is characterized in that a DSOGI-QSG algorithm is adopted in a phase-locked loop, a difference node is introduced on a second-order generalized integrator SOGI structure in the DSOGI-QSG to improve the DSOGI structure, and the improved DSOGI-QSG structure is obtained and can suppress the influence of a direct current component on extraction of each parameter; a specific subharmonic elimination module structure is additionally arranged at the front end of the SOGI structure to serve as a front harmonic filtering cascade module, then the amplitude is corrected through a correction coefficient, and finally filtered signals are input into the SRF-PLL. A cascade harmonic elimination module is constructed in front of the QSG to suppress the distortion harmonic influence, and meanwhile, the QSG structure is optimized, so that the QSG structure can eliminate the direct current amount in the signal, the good characteristics of the traditional DSOGI-PLL are reserved, and meanwhile, the influence of the current bias amount, harmonic distortion and three-phase imbalance of the power grid synchronization signal on the phase locking speed and accuracy can be effectively reduced; and the system performance and applicability are improved.

The invention relates to a double-frequency filtering metasurface design method based on topological optimization. The method comprises the following steps: establishing a two-dimensional simulation model comprising a double-frequency filtering metasurface matrix and a scatterer; according to a preset target forbidden band, taking a forbidden band frequency covering frequency doubling target interval as a fitness function, coding the binary matrix representing material distribution as a chromosome to perform optimization iteration of the chromosome, and obtaining the chromosome with the maximum fitness function value; in optimization iteration, material distribution corresponding to chromosomes is constructed on a two-dimensional simulation model, an energy band structure of the two-dimensional simulation model is obtained, and a fitness function value is calculated; and according to the binary matrix of the chromosome with the maximum fitness function value, outputting final optimized material distribution of the double-frequency filtering metasurface, and performing performance verification on a result through simulation to obtain the double-frequency filtering metasurface of which a fundamental frequency wave can be blocked through a double-frequency wave. Compared with the prior art, systematic optimization of the frequency doubled sound filtering scene is realized.

The invention discloses a transformer fault diagnosis method, system and equipment based on harmonic injection and a storage medium, and the method comprises the steps: installing a vibration sensor on a transformer body, collecting steady-state and dynamic vibration signals, and carrying out the preprocessing of the vibration signals; time domain feature analysis is carried out on the collected vibration signals, frequency domain feature analysis is carried out on the vibration signals, and then spectrum complexity is analyzed; normal ranges of RMS values, peak factors and odd-even harmonic ratios are set through historical data, and if the data exceed the set ranges, the fan influence is further analyzed; analyzing in combination with a power system operation mode, and then performing fault judgment based on a machine learning classification algorithm; if the direct current magnetic bias is detected, an HVDC operation mode is adjusted; and if harmonic injection is detected, an active harmonic filter is adopted to suppress harmonic interference. The harmonic current is detected and compensated in real time, the voltage and current waveforms of the power grid are improved, the harmonic pollution of the power grid is reduced, and the electric energy quality is improved.

The invention provides a fundamental frequency calculation method for adaptive parameter adjustment, which is suitable for power signal frequency estimation under a noise interference or multi-harmonic background. Firstly, voltage and current signals are subjected to analog-to-digital conversion to obtain digital signals, a CIC filter in a non-recursive form is adopted for multi-stage extraction processing, and the data complexity is reduced; sequentially inputting the extracted signals into a plurality of notch filters with feedback structures for harmonic filtering; and iteratively updating the center frequency parameter of the notch filter through a gradient descent method, and when the error function is minimized, the current frequency parameter is the fundamental frequency of the signal. The method has the characteristics of fast convergence, strong robustness and high calculation precision, and is suitable for scenes of electric energy metering, frequency protection and the like.

The three-phase LC harmonic filter reactor comprises three magnetic core assemblies, the three magnetic core assemblies are annularly distributed, each magnetic core assembly comprises an upper cover magnetic core, a lower cover magnetic core and two center pillar magnetic cores, the top ends of the two center pillar magnetic cores are connected with the two ends of the upper cover magnetic core respectively, and the top ends of the two center pillar magnetic cores are connected with the two ends of the lower cover magnetic core respectively. The upper cover magnetic core and the lower cover magnetic core are arranged in the two magnetic core assemblies, the bottom ends of the two middle column magnetic cores are connected with the two ends of the lower cover magnetic core respectively, in the two magnetic core assemblies, every two adjacent middle column magnetic cores form a middle column magnetic core set, the middle column magnetic core sets are sleeved with coils, and the upper cover magnetic core, the lower cover magnetic core and the middle column magnetic cores are all metal magnetic powder cores. According to the structure, the precision of three paths of inductance values can reach the difference within 3%, meanwhile, each phase of inductance has only one coil, the processing difficulty that a traditional coil needs 8-shaped winding is avoided, the number of turns of the three-phase coils is completely the same, the process that a large amount of working hours are spent on adjusting the number of turns of the coils or padding air gaps to meet inductance balance in the production link is reduced, and the production efficiency is improved. Copper material consumption is saved, and production cost is reduced.

A system includes a voltage-controlled oscillator (VCO), a first second-order harmonic filter coupled to the VCO, wherein the first second-order harmonic filter includes a first tunable capacitor, and a second second-order harmonic filter coupled to the VCO, wherein the second second-order harmonic filter includes a second tunable capacitor. The system also includes a measurement circuit coupled to the VCO, wherein the measurement circuit is configured to measure a voltage swing of the VCO. The system also includes a control circuit coupled to the measurement circuit, the first tunable capacitor, and the second tunable capacitor.

The invention provides a filter circuit, a filter control device and a filter control method. The filter circuit comprises a first inductor device, a first capacitor device and a plurality of filter branches; the first end of the first capacitor device is used for connecting a stator of the generator and the first end of the first inductor device, and the second end of the first capacitor device is connected with the plurality of filter branches; the plurality of filtering branches are connected in parallel; the second end of the first inductor device is connected with the double-fed converter; at least part of the filtering branches comprise resonance parameter adjusting devices, and the resonance parameter adjusting devices in different filtering branches are different; the filtering branch also comprises an on-off control device which is used for controlling the on-off of the filtering branch and the first inductance device. According to the mode, different resonance parameter adjusting devices can be communicated, so that frequency band harmonic waves existing in a current loop are filtered out, the harmonic waves of all frequency bands can be effectively filtered out by connecting the different resonance parameter adjusting devices, a wide-frequency-band filtering function is achieved, and the harmonic wave filtering effect of all the frequency bands is improved.

The application relates to a high-voltage power-taking capacitor protection and harmonic suppression system and a circuit thereof, and belongs to the field of power distribution network intelligent control switch power taking. The circuit is arranged between an isolation transformer and a feeder terminal unit (FTU), and comprises an input protection circuit for suppressing input surge overvoltage and fast pulse group, a harmonic filter circuit for filtering out harmonics, a signal acquisition and conditioning circuit for converting an alternating current signal into a direct current voltage signal, and a control protection circuit for comparing the direct current voltage signal with a preset reference voltage. The system further comprises a high-voltage capacitor voltage divider, an isolation transformer and the feeder terminal unit (FTU). The application effectively solves the problem that harmonic interference, surge impact and overvoltage risk coexist in the high-voltage power-taking system, greatly improves the safety and reliability of the operation of the rear-end FTU equipment under the premise of ensuring the accuracy of voltage signal measurement and power supply continuity.

The application relates to the technical field of harmonic filters, in particular to a harmonic filter for power quality improvement, which comprises a harmonic filter body, and first and second sealing connection plates are respectively fixedly connected to both ends of an outer frame cover in the harmonic filter body through bolts. Two first and second sliding outer frames which are uniformly arranged in the harmonic filter body can be slid out of the inner part of the outer frame cover after the first sealing connection plate is removed according to the needs of maintenance, installation and disassembly, an electric push rod which is uniformly arranged on the second sliding outer frame is started to control the forward movement of a connection plug which is inserted into the inner part of a butt joint connection column, no matter whether a driving control gear is arranged on a sliding driving gear plate on the first or second sliding outer frame, as long as the electric motor drives the driving control gear to rotate and operate, the first or second sliding outer frame is synchronously slid outwards.

Embodiments pertain to methods and system for detecting and / or characterizing at least one object in a scene that is being propelled by at least one rotating device. The methods may include transmitting electromagnetic radiation (EM) into free space towards the scene; receiving, from the scene, EM radiation reflections that are reflected from at least one rotating device of the at least one object that is present in the scene; and processing the reflections to detect, based on harmonic characteristics of the reflected EM radiation, the presence of the at least one object in the scene. In some examples, the methods include processing the reflections to characterize, based on the harmonic characteristics of the reflected EM radiation, the type of the at least one detected object. In some examples, the processing comprises applying an harmonic filter on the reflected EM radiation to detect harmonics of the reflected EM radiation.

Various embodiments of the present disclosure provide a neutral and / or ground harmonic filter system for mitigating neutral and / or ground harmonics.

The invention belongs to the field of intelligent power distribution systems, and provides a design method and system for an online harmonic monitoring system of a power system, and the method comprises the following steps: collecting a voltage signal of a transformer in a transformer substation in real time through a voltage transformer; performing frequency domain analysis on the acquired voltage signal by applying Fourier transform, and extracting each frequency component in the signal; setting a time window and a time interval, obtaining the frequency corresponding to the frequency component with the maximum amplitude in each time interval, and recording the frequency as the highest frequency; obtaining a harmonic super-harmonic frequency difference through the highest frequency, and obtaining a harmonic violent wave band time window through the harmonic super-harmonic frequency difference; and obtaining a harmonic violent band ratio through the harmonic violent band time window, and monitoring the operation condition of the power system through the harmonic violent band ratio. According to the design method provided by the embodiment of the invention, the problem can be quickly detected at the initial stage of harmonic pollution, and the harmonic filter is timely started or the load distribution is adjusted, so that the stability of the power system is ensured.

An amplifier includes a signal input terminal for inputting an input signal; a voltage input terminal for inputting a power supply voltage; an amplification circuit for generating an amplified input signal based on the input signal, wherein the amplified input signal has a fundamental frequency, a first harmonic, and a second harmonic, wherein the first harmonic is the second harmonic of the fundamental frequency, and the second harmonic is the third harmonic of the fundamental frequency; a harmonic filter circuit coupled between the voltage input terminal and the amplification circuit for filtering the first harmonic and the second harmonic; and a signal output terminal coupled to the harmonic filter circuit for outputting an output signal based on the amplified input signal.

This invention discloses a specific harmonic cancellation pulse width modulation method suitable for digital power amplifiers. It involves fitting a periodic signal f(t) to obtain an approximate function g(t) and performing Fourier analysis to derive the Fourier coefficients b of the current. n Wherein, the Fourier coefficient b n With the switching angle sequence α q 'As a parameter; for the switching angle sequence α q 'Optimization is performed to obtain the optimized switching angle sequence α' q According to α q The corresponding circuit is controlled by pulse width modulation to output a voltage waveform with specific harmonics filtered out. This invention obtains a specific switching angle sequence by establishing and solving a system of nonlinear equations. The output voltage waveform with specific harmonics filtered out is then modulated based on this switching angle sequence. This method can generate the desired frequency domain component and eliminate unwanted harmonics. It is also applicable to the design of multiple H-bridge units. At the same switching frequency, this method can output higher-order harmonics than other modulation methods, thus reducing switching losses. Furthermore, its excellent harmonic suppression performance saves hardware costs.

The invention relates to the field of current reducing systems, and particularly discloses a system and a method for reducing current and improving electric energy quality, comprising at least one current limiting module, a first current transformer, at least one capacitive module, a first switch, a second switch, a third switch, a fourth switch, a control protection system and a voltage transformer, the current limiting module is connected in series with the third switch, then connected in parallel with the fourth switch, and then integrally connected in series with the first current transformer; the capacitive module is connected in series with the second switch and then connected in parallel with the third switch; one end of the first switch is connected with the capacitive module and a connecting line of the second switch, and the other end of the first switch is grounded. Functions of current limiting, reactive compensation, series compensation, harmonic filtering and the like can be realized, and the number of equipment is reduced.

Embodiments herein relate to a clock distribution network. In one aspect, the network includes a resonant transmission line-based architecture which includes a single inductive-capacitance (LC) termination along the distribution and an additional capacitive termination at the end of the distribution to independently tune the primary and secondary resonance frequencies of the network and perform 3rd-harmonic filtering. The LC termination can include a coil inductor or a short-circuited termination line with parallel conductors to provide an inductance.

The invention discloses a method for measuring insertion loss of a harmonic filter. Measurement is carried out under the condition of rated voltage and rated current of a 50Hz / 400Hz power grid actually used by the harmonic filter, the method is simple, operation is convenient, and data are real and visual. Meanwhile, high-end equipment such as a network analyzer and a measurement receiver is not needed, and the measurement system is low in cost and reliable in operation. According to the method disclosed by the invention, the acquired analog data is transmitted after A / D conversion, so that the measured data is real and reliable and is prevented from being interfered by an electromagnetic environment. Finally, data processing is completed by means of existing mature software, a measured result is displayed in a frequency spectrum graph, the system is stable, new software does not need to be developed, time and money are saved, and efficiency is high.

The utility model provides a receiving and transmitting circuit of a 5G signal monitor. The receiving and transmitting circuit comprises a receiving and transmitting port, a receiving link, a transmitting link, a switching module and a frequency conversion module, the receiving and transmitting port is coupled to the receiving link and the transmitting link through the switching module, and the receiving link and the transmitting link are coupled to the frequency conversion module. The frequency conversion module is used for receiving the radio frequency signal transmitted by the receiving link and performing down-conversion processing or performing up-conversion processing on an analog baseband signal and then transmitting the processed signal to the transmitting link; the receiving link comprises a low-noise amplifier, a low-noise bypass amplifier and a gain amplifier which are connected in sequence, and the low-noise amplifier is in coupling connection with the switching module; the transmitting link comprises a driving amplifier, a power amplifier and a harmonic filter which are connected in sequence; and the harmonic filter is coupled with the switching module. According to the scheme, a direct frequency conversion structure is adopted, and the scheme cost and the total power consumption of the transceiver are reduced.

The present application relates to a kind of compact railway energy regulation complex and its control method, including the converter unit with the core of medium-frequency transformer, the magnetic field of medium-frequency transformer is to the decoupling inductance of collision and filter capacitor and is constituted the second harmonic filter branch of converter unit DC side, filter each converter unit DC side in single-phase conversion system The second harmonic component is removed.Compact railway energy regulation complex uses double-phase shift control and passive control etc.Control method, can accurately control the power flow distribution of two power supply arms and realize traction transformer primary side three-phase current balance control, and using the linear quadratic regulator LQRI control method based on band integration is carried out energy comprehensive regulation, can effectively suppress the voltage fluctuation of feeder side, improve the comprehensive energy utilization rate and new energy consumption rate of electric railway system.Because of the existence of medium-frequency transformer, compared with the electric energy regulation device with the basic topology of traditional railway power regulator, compact railway energy regulation complex has higher integration.

Various embodiments of the present invention provide a neutral and / or ground harmonic filtering system for suppressing neutral and / or ground harmonics.

The utility model provides a wireless communication system of an intelligent meter. The wireless communication system comprises an antenna, a harmonic filtering module, a radio frequency front-end module, a conditioning and frequency selecting module, a transceiving modem and a main control module which are connected in sequence, the antenna is in wireless communication connection with handheld equipment; the conditioning and frequency-selecting module comprises a frequency-selecting chip and a signal conditioning unit; the signal conditioning unit comprises a first diode and a second diode which are reversely connected in parallel; the output end of the radio frequency front end module is connected with the input end of the frequency selection chip; the output end of the frequency-selecting chip is connected with the transceiving modem; the anode of the first diode is connected with the ground, and the cathode of the first diode is connected between the output end of the radio frequency front end module and the input end of the frequency selection chip. According to the utility model, the synchronization of wireless data transmission stability and transmission distance can be obviously improved, and the number of network transmission relay devices can be reduced.

The invention relates to the technical field of air compressor systems, and discloses an energy-saving air inlet system of an air compressor, which comprises the following modules: a traveling wave thermoacoustic refrigeration module for performing passive refrigeration on inlet air by using pressure pulsation energy in a main air inlet pipeline; the acoustic impedance matching and harmonic filtering coupling structure is used for optimizing sound energy transmission between modules and purifying driving sound waves; the self-adaptive Helmholtz resonance pressurization module is provided with variable geometric parameters and is used for realizing pulsating pressurization; and a cooperative control unit. And the cooperative control unit controls variable geometric parameters of the self-adaptive Helmholtz resonance pressurization module according to the real-time operation working condition of the compressor, so that the natural resonance frequency of the self-adaptive Helmholtz resonance pressurization module is dynamically matched with the fundamental frequency of air inlet pulsation. According to the air compressor, cooperative work of air inlet passive refrigeration and all-working-condition self-adaptive resonance pressurization is achieved, and the volume efficiency and the system energy efficiency of the air compressor are remarkably improved.

The application discloses a kind of based on network type SVG's direct current converter station optimization method and system, it is related to direct current transmission technical field, by connecting N groups network type SVG in the AC measurement of direct current converter station;Network type SVG includes transformer, starting resistance and three bridge arms SVG valve connected in turn;Every bridge arm of the three bridge arms SVG valve includes several full-bridge sub-modules;Again according to the reactive power compensation demand, harmonic filter demand and charging limit demand of converter valve in direct current converter station, the number of groups of network type SVG and the parameters of SVG valve, transformer and starting resistance in network type SVG are calculated, and the network type SVG in the direct current converter station is set by the above parameters.The embodiment of the application can reasonably configure network type SVG in direct current converter station, realize converter station reactive power compensation and harmonic filter function, simultaneously give full play to SVG capacity to provide quick reactive power support to AC system to help fault recovery, improve the stability of direct current transmission system access AC power grid, play system support superiority.

A design method for a mutual inductance coupled triple-tuned Foster-type filter, comprising: Step1. Initially determine the inductance and capacitance values of each branch in the filter based on the driving point impedance function of the LC one-port network; Step2. Determine the cross-sectional dimensions of the wires of each filtering coil; Step3. Substitute the self-inductance and mutual inductance formulas of the filtering coils into the mutual inductance coupling equations of the circuit, and solve the equations by the Newton-Raphson method to obtain the number of turns, radius, and spacing of each coil; Step4. Verify the effectiveness of the filter design scheme. This device arranges multiple disk coils coaxially, which can greatly reduce the floor area of the filtering device and achieve the function of multi-harmonic filtering. Hollow disk coils are used to improve the utilization rate of the wire, and the self-inductance and mutual inductance of the disk coils are accurately calculated with corresponding formulas; in the design, the coil with a larger size is split into several coaxial small coils to further compress the floor area of the coil group; the mutual inductance coupled triple-tuned Foster-type filter provided by this method fully considers the actual manufacturing details and has high practical value.

The utility model discloses a harmonic filtering power distribution cabinet, relates to the technical field of power distribution cabinets, and aims to solve the problems that a conventional power distribution cabinet lacks an electric leakage monitoring management and control structure and function, has limitation in adaptation to a wet working occasion on a ship, and needs to be improved in overall practicability. A harmonic filter is arranged at the top end in the cabinet body, a dehumidification cooler is arranged at the bottom end in the cabinet body, an insulating plate is fixedly installed on the side surface of the cabinet body, an electric box is fixedly installed on the outer surface of the insulating plate, and an insulating seat is fixedly installed on the upper end face of the electric box; a mounting hole is formed in the side surface of the insulating seat, a conducting rod is buckled and mounted in the mounting hole, and one end of the conducting rod abuts against the side surface of the cabinet body. The effects that whether the cabinet body leaks electricity or not can be monitored in real time, the cabinet body can adapt to the humid working environment, and practicability is high are achieved.

The utility model provides a filter circuit, a filter control device and a frequency converter system. The filter circuit comprises a first inductor device, a first capacitor device and a plurality of filter branches; the first end of the first capacitor device is connected with the first inductor device, and the second end of the first capacitor device is connected with the plurality of filter branches; the plurality of filtering branches are connected in parallel; at least part of the filtering branches comprise resonance parameter adjusting devices, and the resonance parameter adjusting devices in different filtering branches are different; the filtering branch also comprises an on-off control device which is used for controlling the on-off of the filtering branch and the first inductance device. According to the mode, different resonance parameter adjusting devices can be communicated, so that frequency band harmonic waves existing in a current loop are filtered out, the harmonic waves of all frequency bands can be effectively filtered out by connecting the different resonance parameter adjusting devices, a wide-frequency-band filtering function is achieved, and the harmonic wave filtering effect of all the frequency bands is improved.

The present invention provides a multi-mode networking adaptive monitoring system for weak signals in power transmission and transformation construction, relating to the technical field of multi-mode networking. The system comprises a multi-modal module for deploying multi-modal sensing units at key monitoring points on power transmission and transformation equipment to collect vibration, partial discharge, leakage current, and environmental parameter signals. The system then processes these signals through an electromagnetic shielding enclosure and a built-in harmonic filtering circuit to obtain raw monitoring signal data. A detection module inputs the raw monitoring signal data into a chaos-enhanced weak signal detection device, extracting fault feature vectors by capturing sudden changes in the attractor phase diagram and time-domain waveform thresholds. By utilizing multi-modal sensing and adaptive networking technologies, the present invention enables monitoring of weak signals in power transmission and transformation and timely extraction of fault features, thereby improving the accuracy and adaptive capabilities of fault warnings.