67 results about "Harmonic filtering" patented technology

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.

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.

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.

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 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 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.

The present application relates to a kind of full differential lissajous frequency modulation MEMS gyroscopes, comprising: gyroscopic sensing unit, differential interface unit;Gyroscopic sensing unit, for generating resonance state in response to control signal, and angular rate signal is obtained in resonance state, first signal and second signal are obtained by differentially processing angular rate signal, and first signal and second signal are sent to differential interface unit;Differential interface unit, for providing control signal to gyroscopic sensing unit, and the first signal and second signal received are subjected to difference frequency harmonic filtering processing and synchronous demodulation processing, filter out the interference signal existing in first signal and second signal, obtain the angular rate signal without interference.The method can eliminate the influence of interference signal on detection accuracy, widen the usable bandwidth and the unspurious dynamic range of lissajous frequency modulation MEMS gyroscope, greatly improve the detection accuracy of lissajous frequency modulation MEMS gyroscope.

1. The name of the design product: heavy harmonic filter compensation reactor. 2. The use of the design product: used in industrial and civilian power distribution systems to achieve harmonic control, reactive compensation and comprehensive power quality control, and to improve the performance and stability of the power grid. 3. The design points of the design product: in shape. 4. The picture or photo that best shows the design points: perspective view 1.

The invention discloses a transformer comprehensive loss measurement system and method based on SF6 gas insulation and multi-range integration, and the system comprises a three-phase independent high-voltage measurement unit, a data collection unit, an AD conversion module, a signal preprocessing unit, a calculation module, a data caching unit, a communication interface, a data uploading and display unit, and a control host. The method comprises the following steps: firstly, collecting signals, then carrying out AD conversion, then carrying out harmonic filtering, and then carrying out a calculation process; then storing the data; and then the stored data is transmitted to the control host, and then real-time waveform display and report output are performed, so that the contradiction between wide range and high precision is fundamentally solved, field interference and overvoltage impact can be effectively resisted, and the test efficiency and the automation level are greatly improved. And the safety risk caused by manual operation in a high-voltage area is avoided.

Synchronizing the grid-side harmonic filter and pre-charged battery capacitors in a modular multilevel converter can be achieved by: disconnecting a transmission circuit breaker on a first path between the grid and the converter system; closing a pre-charge contactor on a second path between the grid and the converter system, the pre-charge contactor comprising a set of pre-charge resistors; connecting the grid to the converter system and harmonic filter via the second path; selectively charging the battery capacitors in the converter system until a charge threshold is reached, wherein a smaller subset of the battery capacitors is charged at a given time compared to an earlier time, and each battery capacitor is charged to a higher battery voltage compared to an earlier time; and closing the transmission circuit breaker, and simultaneously connecting the generator to the converter system via a generator circuit breaker while closing the pre-charge contactor.

The invention discloses a permanent magnet synchronous motor adaptive sliding mode observation method based on fuzzy logic and DSOGI-PLL, and belongs to the technical field of motor sensorless control. According to the method, aiming at the buffeting and phase lag problems of a traditional sliding mode observer, a fuzzy logic controller is adopted to dynamically adjust the sliding mode gain and the F (s) function slope coefficient, and the buffeting of the system is effectively inhibited; meanwhile, a double-second-order generalized integrator phase-locked loop is introduced to carry out orthogonal decomposition and harmonic filtering on the back electromotive force signal, a fundamental component is accurately extracted, and phase delay is reduced. The method is embedded into a permanent magnet synchronous motor vector control system and can replace a mechanical position sensor to realize high-precision rotation speed and position estimation. Simulation and experiment results show that the method has remarkable advantages in the aspects of buffeting suppression and counter electromotive force estimation precision.

The invention belongs to the technical field of short-wave radio stations, and relates to a heat dissipation structure for a high-power harmonic filter and an installation method of the heat dissipation structure. The heat dissipation structure comprises a plurality of heat dissipation grounding columns which are distributed between a harmonic filter mounting surface and a short-wave radio set casing; the harmonic filter mounting surface is an area which is arranged on the printed circuit board and is used for mounting and fixing the harmonic filter, and a ground network copper-clad area is arranged on one surface, close to the heat dissipation grounding columns, of the harmonic filter mounting surface and is used for realizing electrical connection with the plurality of heat dissipation grounding columns. According to the structural design of the heat dissipation grounding pole, the area of a printed circuit board of a harmonic filter is not increased while the heat dissipation efficiency is improved and the grounding resistance is reduced, and the design concept of miniaturization of airborne equipment is met.

The invention relates to an electric energy quality optimization control method and system for an electric hydrogen production system, and the method comprises the steps: extracting the frequency and phase information of a power voltage fundamental wave, and designing a frequency-adaptive fractional order repetitive controller based on the frequency of the fundamental wave; based on the phase information, harmonic current and reactive current are separated from the load side current of the electric hydrogen production system, and the sum of the harmonic current and the reactive current serves as instruction current; the method comprises the following steps: acquiring actually output compensation current from an output end of an active power filter (APF), and detecting a direct-current side capacitor voltage of the APF; error signals of the instruction current and the compensation current and error signals of the APF direct current side capacitor voltage and the reference target value are superposed to serve as input quantity, the input quantity is input into a controller to form a control signal, then SPWM is controlled to generate modulation waves, a power device switch is driven, the compensation current is generated, and harmonic compensation of the power grid output current is achieved. The method has the advantages of higher stability and shorter adjustment time in harmonic filtering control.

The utility model discloses a balanced sense quantity three -phase LC harmonic filter reactor, including three magnetic core assemblies and three middle columns magnetic cores, three magnetic core assemblies are annular distribution, the magnetic core assembly includes upper cover magnetic core and lower cover magnetic core, and two adjacent magnetic core assemblies are connected through the middle column magnetic core, the top of middle column magnetic core is connected with the two upper cover magnetic cores of adjacent magnetic core assembly simultaneously, the bottom of middle column magnetic core is connected with the lower cover magnetic core of adjacent magnetic core assembly simultaneously, the coil is sheathed on the middle column magnetic core, and the upper cover magnetic core, lower cover magnetic core and middle column magnetic core are all metal magnetic powder core. This structure can make three -way inductance precision reach the difference within 3%, and each phase inductance has only one coil, avoids the processing difficulty that traditional coil needs 8 -shaped encircling, and three -phase coil turns are completely same, reduces the production link and spends a lot of working hours to adjust coil turns or pad air gap to satisfy inductance balance's technology, saves copper material consumption, reduces production cost.

The invention discloses a hybrid offshore wind power sending-out system based on SiC-MOSFET type MMC and diode uncontrolled rectification, an offshore converter station is formed by connecting a DRU and an MMC in parallel, an offshore AC bus can be configured with an SVG and a capacitor, the DRU undertakes main active power transmission, the offshore MMC provides voltage support and harmonic filtering, and the MMC is connected with the DRU and the MMC in parallel. The fan provides limited reactive power compensation through an active-reactive power curve on the premise of full active power operation, and the land MMC maintains the DC voltage stable. The offshore MMC in the system adopts SiC-MOSFET straight string sub-modules and an active clamping voltage sharing technology, the number of the sub-modules is reduced, the system efficiency is improved, flexible compensation of DRU reactive power consumption is achieved through three types of reactive power compensation schemes, and economical efficiency and dynamic performance are both considered. Therefore, the system provided by the invention is suitable for high-capacity wind power transmission in deep and far sea, and has a good engineering application prospect.

The utility model relates to a composite filter circuit comprising a first line and a second line which are connected to a variable frequency power supply. The first circuit comprises a power transformer, a frequency converter, a motor and a variable-frequency power supply which are connected in sequence; the second line comprises a first filter used for higher harmonic filtering, a second filter used for electromagnetic interference filtering, an isolation transformer and electrical equipment. The variable frequency power source, the first filter, the second filter, the isolation transformer and the electrical equipment are connected in sequence. According to the utility model, through combination of the first filter and the second filter, high-frequency harmonic current with radiation energy and high-frequency harmonics during operation of a motor and electrical equipment in the circuit can be weakened, harmonic pollution is reduced, and the stability of the circuit is improved.

The invention discloses a frequency converter. The frequency converter comprises a first chamber, a second chamber and a third chamber which are sequentially arranged in a first direction, the protection device is arranged in the first cavity and comprises a plurality of main circuit breakers used for controlling on-off of the frequency converter and an external power source, all the main circuit breakers achieve synchronous opening and closing through a linkage mechanism, and the linkage mechanism comprises a support base, a lifting plate, a rotating rod and a connecting rod assembly. When the rotating rod rotates, the connecting rod assembly drives the lifting plate to ascend and descend along the support base so as to stir the operation handle. And the harmonic filtering device is arranged in the second cavity and is used for being electrically connected with the main circuit breaker. And the frequency conversion device is arranged in the third cavity and is electrically connected with the harmonic filtering device. The frequency converter is reasonable in layout, and the use safety of the frequency converter is improved.

The utility model relates to the technical field of electromagnetic interference (EMI) filtering, in particular to an EMI filtering optimization structure for a switching power supply. The EMI filter circuit is electrically connected with the input end of the rectifier bridge BD1, the output end of the rectifier bridge BD1 is electrically connected with the drive circuit through the filter module, the drive circuit is electrically connected with the primary side of the transformer T1, the dotted terminal of the secondary side of the transformer T1 is electrically connected with the anode of the diode D3, and the synonym terminal of the secondary side of the transformer T1 and the cathode of the capacitor EC3 are grounded. The cathode of the diode D3 is electrically connected with the anode of the capacitor EC3; the filtering module has a harmonic filtering function; the mounting position of the secondary side of the transformer T1 on the circuit board is far away from the EMI filter circuit; the problems that noise is introduced by subsequent harmonic filtering of the EMI filter circuit 1 and self EMI filtering fails due to improper layout of the circuit board are solved.

The invention provides a harmonic filter integrated in an ultra-short wave power amplifier in a matching manner by using a load traction technology, which comprises the following steps: setting different frequency points for a broadband power amplifier, and determining target impedance values corresponding to the different frequency points based on a preset test condition by combining the load traction technology; determining an input impedance network of the harmonic filter corresponding to the target impedance value according to the target impedance value, and matching an output transmission line corresponding to the input impedance network through impedance conversion by adopting a multi-order elliptical low-pass network model; an elliptical low-pass model is arranged in the harmonic filter, and a transmission zero point is generated through parallel resonance to suppress harmonic waves. According to the method disclosed by the invention, a module cascade matching joint debugging link can be omitted to the greatest extent, functional indexes of the module assembly are correspondingly improved, the volume space is saved, the integrated design is realized, the application, installation and operation are simple and convenient, and the performance is stable and reliable.

The invention relates to the technical field of electronic power, in particular to a box-type substation overload monitoring device and method, and the method comprises the steps: connecting a harmonic filter and an energy storage power supply into a box-type substation, carrying out the dynamic control of the harmonic filter and the energy storage power supply, and achieving the overload monitoring, and performing energy storage power supply control according to the suppression capability of the harmonic filter on each harmonic frequency and a preset overload correction coefficient. When overload is detected again, the overload correction coefficient is updated according to the overload quantity obtained by the harmonic filter and the energy storage power supply in the historical working process and the suppression capability of each harmonic frequency, so that the difference between the residual quantity of the energy storage power supply and the output quantity of the energy storage power supply is maximum; and then controlling the energy storage power supply based on the updated overload correction coefficient. According to the overload monitoring device, the accuracy of active overload monitoring of the box-type substation can be improved.