25results about How to "Good harmonic suppression effect" patented technology

The invention discloses a harmonic control method and system of a frequency converter. The method comprises the following steps: acquiring an output voltage signal and a bus voltage signal of the frequency converter in a current time period; performing spectral analysis on the output voltage signal, and constructing a first frequency distribution characteristic curve; correcting the first frequency distribution characteristic curve according to the bus voltage signal to obtain a second frequency distribution characteristic curve; if the output frequency signal of the frequency converter generates frequency drift, tracking the frequency drift of the output frequency signal to obtain a frequency drift rule; performing voltage waveform distortion analysis on the output voltage signal to obtain a total harmonic distortion rate; performing parameter optimization on the filter according to the total harmonic distortion rate and the frequency drift rule, so that the third frequency distribution characteristic of the filter is matched with the second frequency distribution characteristic; in the next time period, the optimized filter is adopted to carry out frequency converter harmonic suppression; the harmonic suppression effect of the frequency converter can be effectively improved, and the power supply quality of a power grid is improved.

The invention discloses a CPT wireless energy transmission higher harmonic filter and a CPT wireless energy transmission system based on the same, and relates to the technical field of wireless power transmission. Comprising more than one harmonic filter circuit, wherein the CPT wireless energy transfer higher harmonic filter is connected between a CPT wireless energy transfer Class EF inverter and a CPT wireless energy transfer transmitting terminal compensation network; each harmonic filter circuit comprises a filter inductor and a filter capacitor; one end of the filter inductor is connected with a drain electrode of an MOS (Metal Oxide Semiconductor) tube in the CPT wireless energy transfer Class EF inverter and an input end of the CPT wireless energy transfer transmitting end compensation network; the other end of the filter inductor is connected with one end of the filter capacitor, and the other end of the filter capacitor is grounded. According to the invention, the harmonic suppression capability can be improved, the size of filter elements is reduced, the stability of resonant frequency is enhanced, and the design and debugging process is simplified.

The invention belongs to but not limited to the technical field of antennas, and particularly relates to an automatic tuning transmitting antenna and method for RS103 testing, and the antenna comprises an antenna array pipeline which enables a length-variable antenna array to stretch out and draw back in the pipeline; the tunable antenna array is made of soft and thin copper foil, can bear large current and is wound on a rotary column of the program control motor, and the length of the antenna array is adjusted through rotation of the program control motor; the optical fiber interface is connected with an optical fiber of a program control motor, and program control of the motor used by the antenna array is completed through program control software of the test system; the coaxial port is connected with an output power coaxial line of the radio frequency power amplifier, so that the output power of the radio frequency power amplifier is transmitted to the antenna array, and the antenna array generates required field intensity at a position of 1m; and the program control motor is used for controlling the lengths of the antenna arrays at different frequencies, controlling the rotation of the motor through the program control software of the test system, and adjusting the lengths of the arrays.

The invention discloses a continuous reactive power compensation circuit, which comprises a power grid, a reactor L, a shunt capacitor bank and an adjustable capacitor, one end of the electric reactor L is connected with a power grid, the other end of the electric reactor L is connected with the shunt capacitor bank and the adjustable capacitor, the shunt capacitor bank comprises n alternating-current capacitors which are mutually connected in parallel, and the adjustable capacitor is composed of four I GBTs (T1-T4), four diodes (D1-D4) and one direct-current capacitor Cdc; by monitoring and analyzing reactive power of a power grid, reactive power compensation quantities in different time periods are decomposed into a constant quantity part and a fluctuation quantity part, and a shunt capacitor bank is adopted to compensate the constant quantity part and an adjustable capacitor is adopted to compensate the fluctuation quantity part respectively; therefore, the device has the advantages of high control precision and high response speed, and is easy to expand, and the compensation capacity is improved, so that the comprehensive compensation capability of the device is improved.

The invention discloses a permanent magnet synchronous motor harmonic suppression method based on an improved particle swarm algorithm, and relates to the technical field of PMSM harmonic suppression, and the method comprises the steps: S1, obtaining a harmonic current component through the electrical angle and three-phase current of a permanent magnet synchronous motor; s2, constructing an algorithm value function according to the harmonic current component; and S3, obtaining a harmonic suppression result of the permanent magnet synchronous motor based on an improved particle swarm algorithm according to the harmonic current component and the algorithm value function. According to the method, a current component under a rotating reference system is obtained by utilizing multiple synchronous rotating coordinate system transformation, and then a corresponding LPF is selected for filtering so as to extract current harmonics; according to the method, decoupling compensation of current harmonics is carried out by establishing a shift multi-reference system, and compared with other methods, the algorithm is simpler; according to the method, the amplitude and the phase of dead zone compensation by improving the particle swarm optimization are not affected by motor parameters, the iteration speed is high, and the method is not prone to falling into a local optimal solution.

The invention discloses a harmonic control method and system for a frequency converter, the method comprising: obtaining an output voltage signal and a bus voltage signal of the frequency converter in a current time period; performing spectrum analysis on the output voltage signal to construct a first frequency distribution characteristic curve; correcting the first frequency distribution characteristic curve according to the bus voltage signal to obtain a second frequency distribution characteristic curve; if a frequency drift occurs in the output frequency signal of the frequency converter, tracking the frequency drift of the output frequency signal to obtain a frequency drift law; performing voltage waveform distortion analysis on the output voltage signal to obtain a total harmonic distortion rate; performing parameter optimization on a filter according to the total harmonic distortion rate and the frequency drift law to match a third frequency distribution characteristic of the filter with a second frequency distribution characteristic; and using the optimized filter to suppress harmonics of the frequency converter in the next time period. The invention can effectively improve the harmonic suppression effect of the frequency converter and improve the power supply quality of the power grid.

The invention discloses a method and system for improving harmonic suppression of an LLLC type grid-connected inverter under a weak power grid, and the method comprises the steps: building a transfer function model of a current control system of the LLLC type grid-connected inverter, and enabling an active damping link of the current control system of the LLLC type grid-connected inverter to be realized through a first-order voltage feedforward controller; building a simulation model of the current control system of the LRLC type grid-connected inverter, and drawing a z-domain closed-loop zero-pole graph of the control system; and determining a parameter range of a first-order voltage feed-forward controller according to the closed-loop zero pole position of the control system containing the active damping link, and verifying the harmonic suppression capability of the LRLC type grid-connected inverter current control system containing the active damping link. On the basis of an existing sampling system of the grid-connected inverter, grid-connected low-voltage side power grid voltage feedback is adopted, an active damping feedforward controller is constructed, the harmonic suppression capacity of the LRLC type grid-connected inverter under a weak power grid is enhanced, and the current on a C branch is reduced.

The invention discloses an active power filter site selection method and device and a nonvolatile storage medium. The method comprises the following steps: determining a voltage harmonic distortion rate and a current harmonic distortion rate of each node in a multi-node power distribution network system; determining a comprehensive harmonic distortion rate of each node according to the voltage harmonic distortion rate and the current harmonic distortion rate of each node; according to the comprehensive harmonic distortion rate of each node, the comprehensive harmonic sensitivity of each node is determined, and the comprehensive harmonic sensitivity of each node is used for representing the change condition of the comprehensive harmonic distortion rates of other nodes after the active filter is installed at the node; and according to the comprehensive harmonic sensitivity of each node, a target node is determined from each node, and the target node is the node of the target active power filter to be installed. The technical problem that the harmonic suppression effect is poor due to the fact that the position suitable for installation of the active power filter cannot be determined in a power distribution network system in the prior art is solved.

The embodiment of the invention provides a power amplifier which comprises an amplifying circuit used for amplifying a differential signal; the amplifying circuit comprises a first transistor and a second transistor; the first resonance circuit is connected with the output end of the first transistor and the output end of the second transistor; the first inductor is connected with the first resonance circuit and a grounding end; the first inductor and the first resonant circuit form a second resonant circuit; the first resonance circuit and the second resonance circuit are used for suppressing different harmonic waves.

The present invention provides a harmonic injection control system and method for suppressing harmonics and current overshoot, which belongs to the field of permanent magnet motor and drive control. Based on the drawbacks of the traditional harmonic injection control strategy, the harmonic current component of the three-phase current of the permanent magnet synchronous motor is extracted, and the extracted harmonic current component is calculated and PI controlled to obtain an accurate harmonic voltage component, which is then injected into the input terminal u of the SVPWM. α and u β , using the overmodulation processing function in the SVPWM module, the voltage vector action time inside the SVPWM is controlled within the switching cycle, and finally the SVPWM module emits a PWM waveform. The present invention not only realizes the harmonic suppression function of the traditional harmonic injection method, but also has a better suppression effect on the overshoot problem of the motor phase current when the motor changes speed or the load changes suddenly.

The invention discloses a high-reliability complex coefficient repetitive control grid-connected inverter control system and method suitable for a power supply protection scene, and the method comprises the steps: building an LCL type grid-connected inverter mathematical model under an alpha-beta static coordinate system for a three-phase grid-connected inverter, and saving Park transformation and decoupling calculation under a dq coordinate system; a complex coefficient filter H (s) and a complex coefficient repetitive controller are designed to form a double-input double-output control structure, and a complex coefficient imaginary part omega m is set to be equal to a fundamental frequency omega 0, so that the gain of the controller at the fundamental frequency is infinite, and complete tracking of periodic signals is realized; and the dynamic response capability of the system is improved by combining an output feedback control law. According to the method, the grid-side voltage imbalance and harmonic pollution can be effectively suppressed, the grid-connected current THD can be remarkably reduced, and the method has good dynamic control performance and robustness, is suitable for a grid-connected power generation system of new energy such as solar energy and wind energy, and plays an important supporting role in improving the power supply reliability and supply guarantee capability of a power system under the new energy access background.

The invention provides a dynamic voltage control method and system for an energy storage converter, and relates to the technical field of data processing, and the method comprises the steps: carrying out the mathematical modeling of a circuit of the energy storage converter, and building the representation of a voltage in a two-phase rotating coordinate system; according to the expression of the voltage in the two-phase rotating coordinate system, a voltage signal output by the energy storage converter is filtered through a filter, and a filtered voltage signal is obtained; and modulating the filtered voltage signal, and generating a modulation waveform by calculating and distributing the duty ratio of each phase switch so as to control the output voltage of the energy storage converter. Through mathematical modeling, filtering processing, modulation control and an optimization algorithm for simulating the bacterial foraging process, accurate and real-time control of the output voltage is realized, and the response speed and the stability of the system are improved.

The invention discloses a 36-pulse-wave hydrogen production converter based on a controllable pulse wave multiplication balance reactor, and belongs to the technical field of power electronics. The problems that the input current THD and the output voltage ripple of an existing 24-pulse thyristor rectification hydrogen production converter are high, and the number of needed large-current thyristors is large are solved. A nine-phase half-wave thyristor bridge, an auxiliary single-phase thyristor rectifier bridge and a balance reactor with a secondary side form a 36-pulse-wave hydrogen production converter, and the balance reactor with the secondary side and the auxiliary single-phase thyristor rectifier bridge form a controllable pulse wave multiplication balance reactor. The hydrogen production converter with 36 pulse waves can be obtained by controlling thyristors in the nine-phase half-wave thyristor bridge and the auxiliary single-phase thyristor rectifier bridge and reasonably designing the turn ratio of primary and secondary side windings of the balance reactor with the secondary side. According to the scheme of the rectifier, only 18 large-current thyristors are needed, and the rectifier is mainly used for new energy hydrogen production and application scenes with high requirements for electric energy quality.

The invention relates to an active-disturbance-rejection control method with a fast periodic harmonic signal suppression capability, and the method comprises the steps: building a kinetic model based on the controlled object parameters of a single-phase grid-connected inverter; based on the kinetic model, constructing an ESO based on a plug-in repetitive controller; and carrying out harmonic current suppression on the single-phase grid-connected inverter by using the ESO based on the plug-in repetitive controller. According to the invention, plug-in repetitive control is embedded into a disturbance error observation channel of ESO, and an active-disturbance-rejection control method with a rapid periodic harmonic signal suppression capability is provided. According to the method, the limitation of the ESO observation bandwidth is broken through, and the high-frequency harmonic suppression capability of the ESO is improved. And the repetitive controller is designed based on a perfect cancellation theory, so that the error convergence speed of the repetitive controller is improved, and the harmonic suppression capability of the control system is further optimized.

The invention discloses a grid-connected inverter control method and an operation control device, and relates to the technical field of grid-connected inverters, and the method comprises the steps: obtaining a DC bus voltage signal, carrying out the band elimination filtering of the DC bus voltage signal, and obtaining a DC bus harmonic signal; converting the DC bus harmonic signal into a first control signal, and obtaining a second control signal based on inversion current detection; and generating a feedback control signal for an inverter circuit according to the first control signal and the second control signal. The method has the advantages that suppression of power grid background harmonic waves and harmonic waves of output voltage or grid-connected current under a local nonlinear load can be considered at the same time, and the harmonic suppression effect of the grid-connected inverter is improved.

The invention provides a harmonic suppression circuit adopting dual-active modulation, and a rectifier adds a dual-active modulation circuit on a direct current side on the basis of an average value current prediction control strategy. A conventional 12-pulse-wave rectifier is improved into a 12-pulse-wave controllable rectifier with controllable load voltage and low grid-side current harmonic content. According to the parallel 12-pulse rectifier provided by the invention, the THD value of the grid-side current can be reduced, and meanwhile, the load current can be conveniently adjusted.

The present application relates to a kind of LLCCL filter grid-connected energy storage converter wide-frequency collaborative harmonic suppression method and system.Belongs to new energy grid-connected power electronic control and power quality management technical field.The method is set between converter and public coupling point LLCCL filter, and PCC voltage, net side current and filter branch current are collected;According to the power given value, the net side current reference value of bidirectional power operation is generated;Through the active damping of branch current feedback, LLCCL filter resonance peak is inhibited, through the proportional resonant controller containing fundamental wave and low-order harmonic resonance term and PCC voltage feedforward, low-order current distortion caused by background voltage harmonic is inhibited, and high-frequency attenuation is carried out on switching frequency related side frequency component by LLCCL filter.The present application can collaboratively inhibit low-order background harmonic, filter resonance and switching frequency related high-frequency harmonic in the same control framework, improve the grid-connected current quality and operating stability of energy storage grid-connected converter.

The present application discloses a power mixer capable of suppressing the third harmonic of a local oscillator, comprising a local oscillator signal link circuit, a transconductance stage circuit, a switch stage circuit, a common source and common gate stage circuit, and a load circuit. The local oscillator signal link circuit provides two local oscillator signals for the switch stage circuit, one of which has a phase difference of 60 degrees relative to the other. There are two transconductance stage circuits for converting a baseband voltage signal into a current signal. There are two switch stage circuits, which respectively use the two local oscillator signals to up-convert the current signals from the two transconductance stage circuits into the required radio frequency signals. There are two common source and common gate stage circuits, which respectively transmit the radio frequency signals output by the two switch stage circuits to the load circuit. The load circuit realizes the addition of the output currents of the two common source and common gate stage circuits. The function of suppressing the third harmonic is realized through a special phase difference design.

The invention discloses an intelligent harmonic suppression method and system for a stator core for a motor. The method comprises the following steps: acquiring the resistivity of an iron core material, the resistivity of an insulating layer between laminations, the space harmonic order of a stator winding, the working frequency of the motor, the actual working temperature of the iron core, the maximum magnetic flux density of the iron core and the amplitude of a fundamental current; dynamically correcting the eddy current coupling coefficient by combining the actual working temperature of the iron core and the maximum magnetic flux density; calculating a v-order harmonic current amplitude based on the corrected eddy current coupling coefficient; calculating a v-harmonic compensation voltage amplitude; and outputting the matched compensation voltage to the stator winding. The system comprises a parameter acquisition module, an eddy current coupling coefficient correction calculation module and the like. The method solves the problem of harmonic measurement deviation caused by neglecting the dynamic working condition in the existing scheme, improves the adaptability of harmonic suppression, and is suitable for a motor stator core harmonic control scene.

The invention relates to the technical field of motor control, in particular to a motor overmodulation control method based on real-time voltage harmonic detection and compensation. Main harmonic components in output voltage are detected in real time in an overmodulation state, a voltage intelligent compensation strategy is provided, an extra harmonic voltage signal is superposed on the basis of fundamental voltage, the signal is opposite to the harmonic components in time sequence, a compensation signal capable of effectively inhibiting harmonic waves is generated, and finally, the harmonic components in the output voltage are detected in real time. A compensation signal is fused into an original voltage modulation signal through a closed-loop control system, effective suppression of harmonic waves in an over-modulation state is achieved, the electric energy quality of a motor system is remarkably improved, the operation efficiency is optimized, and the service life of the whole driving system is prolonged.

The utility model discloses a calibration source module, which belongs to the field of clock signals and comprises a receiver, a controller, a frequency synthesizer, a switch filter assembly and an attenuator. The receiver is used for receiving a target frequency instruction; the controller is connected with the receiver, and the controller is used for determining configuration parameters and a preset attenuation value of the frequency synthesizer according to the target frequency instruction; the frequency synthesizer is connected with the controller, and the frequency synthesizer is used for performing frequency adjustment according to the configuration parameters to obtain a first frequency; the switch filter assembly is connected with the frequency synthesizer, and the switch filter assembly is used for filtering the first frequency and outputting a second frequency and corresponding power; and the attenuator is connected with the switch filter assembly and the controller, and the attenuator is used for adjusting the second frequency according to a preset attenuation value and outputting a target frequency. Therefore, the harmonic suppression capability of the calibration source module can be improved, and in-band fluctuation can be reduced.

The utility model discloses a kind of harmonic absorption circuits of short wave filter, circuit includes RF power amplifier, low-pass filter module and high-pass filter module, the high-pass filter module is connected in parallel at the input end of the low-pass filter module, and the input end of low-pass filter module and high-pass filter module is respectively connected in parallel by the RF power amplifier output signal. The scheme adopts the mode of connecting high-pass filter in parallel at the input end of low-pass filter, and the passband of high-pass filter is set as the out-of-band harmonic suppression frequency band of wave band, 50Ω power resistance is connected at the output end of high-pass filter to absorb harmonic power, improve the harmonic suppression performance of short wave communication equipment and improve the working life of power amplifier tube.

The embodiment of the invention discloses a new energy grid-connected harmonic suppression regulation and control method and device, electronic equipment and a medium. A specific embodiment of the method comprises the following steps: performing variable window Fourier transform on a power instantaneous value sequence set, and then performing impedance compensation to obtain a compensated power harmonic spectrum diagram set; performing critical point identification on the new energy grid-connected power region to obtain a harmonic resonance critical point set; performing early warning grade division on the harmonic resonance critical point set to obtain an early warning grade critical point set; performing harmonic time sequence prediction on the compensated power harmonic spectrogram and the inverter power information to obtain a harmonic prediction amplitude oscillogram; and performing harmonic suppression control on the early warning grade critical point to obtain grid-connected harmonic regulation and control information, and performing equipment regulation and control processing on the power equipment. According to the embodiment, the early warning accuracy of the harmonic resonance risk and the efficiency of suppressing the harmonic resonance can be improved, the equipment delay is reduced, the safety of the new energy grid-connected equipment is improved, and the power loss is reduced.

This invention discloses a method and system for motor parameter identification based on a multiple synchronous rotating coordinate transformation filter. The method includes: using the motor's voltage and current along the αβ axis, along with position estimation information from a quadrature phase-locked loop (PLL), as inputs to a sliding mode observer to obtain back electromotive force (EMF) observations. The sliding mode algorithm employs a switching function to suppress high-frequency chattering in the back EMF. Furthermore, the harmonic disturbances in the back EMF are filtered out using a multiple synchronous rotating coordinate transformation filter. The fundamental component of the back EMF is then passed through the PLL to obtain the rotor's estimated speed and position information. The proposed multiple synchronous rotating coordinate transformation filter can be applied to sensorless motor control systems, eliminating the fifth and seventh harmonics in the estimated back EMF and exhibiting excellent harmonic suppression. This enables real-time and accurate acquisition of motor position information, improving the control performance of the motor drive system.

The invention provides a grid-connected inverter harmonic suppression method based on double-vector model predictive control, and the method comprises the steps: building an inverter prediction model under an alpha-beta static coordinate system, separating an output current into a fundamental component and a harmonic component, and carrying out the prediction control of the fundamental component and the harmonic component; a dual-target optimization function containing a fundamental wave weight coefficient eta and a harmonic wave weight coefficient gamma is constructed, minimization of an error area between PCC harmonic current and a zero axis is taken as a harmonic suppression target, and a dual-vector model is combined to predict and control a dynamic optimal voltage vector and action time thereof, so that coordinated optimization of fundamental wave power transmission and harmonic suppression is realized. The method can effectively reduce the total harmonic distortion rate at the PCC, improves the electric energy quality of a multi-inverter parallel system, and is suitable for an alternating current bus system containing multiple harmonic sources.