14 results about "Harmonic elimination" patented technology

The application discloses a kind of harmonic elimination device with self-monitoring function and monitoring method, it is related to harmonic elimination device technical field, it includes two relevant parallel zinc oxide resistance, temperature acquisition module and controller, each zinc oxide resistance branch is in series with disconnecting switch, the controller can control the closing and opening of disconnecting switch, the temperature acquisition module is used to collect the temperature information of zinc oxide resistance, the output end of zinc oxide resistance is arranged to ground, and current transformer is arranged on the ground line of zinc oxide resistance.The application has the effect of facilitating the performance degradation of harmonic elimination resistance monitoring.

This application discloses a method for extracting the DC component of an AC signal, comprising: acquiring the AC signal to be processed and its fundamental angular frequency; sequentially performing low-frequency harmonic elimination processing on the AC signal according to the fundamental angular frequency in descending order of harmonic order, wherein each low-frequency harmonic elimination process is configured to: eliminate the current target low-frequency harmonic, while amplifying the high-frequency noise and higher-order harmonics in the AC signal that have not been eliminated, causing the high-frequency noise and higher-order harmonics to trigger amplitude limiting; after completing a preset number of low-frequency harmonic elimination processes, filtering the obtained signal to extract the target DC component from the AC signal; wherein the amplitude limiting value is set to be significantly higher than the amplitude of the target DC component in the AC signal, so that the amplitude of the high-frequency noise and higher-order harmonics after amplitude limiting is far away from the amplitude of the target DC component. This method can achieve fast and accurate extraction of the target DC component.

The application discloses a parallel MPWM modulation method of 3X harmonic elimination, and relates to the technical field of wireless communication.The method comprises the following steps: based on the principle of harmonic elimination, input baseband signals are decomposed into four phase-controlled baseband modulation signals; the baseband modulation signals are subjected to digital up-conversion to obtain intermediate frequency signals; a parallel optimization module is set in a parallel MPWM algorithm, and the intermediate frequency signals are subjected to optimization processing based on the parallel optimization module to obtain four bit pulse sequence codes; the four bit pulse sequence codes are converted into four two-level radio frequency pulse signals; wherein, the sum of the four two-level radio frequency pulse signals is a required five-level radio frequency pulse width modulation signal, the center frequency of the five-level radio frequency pulse width modulation signal is a carrier frequency, and 3X harmonic is eliminated.The application can improve the signal-to-noise ratio, suppress harmonics, and widen the achievable carrier frequency of RF-PWM.

This application relates to the field of electrical equipment operation control technology and discloses a method for overvoltage identification and current limiting harmonic elimination control of voltage transformers. The invention first acquires multi-source response data within a preset analysis period corresponding to the abnormal triggering time, performs tagging processing on topology state information and thermal state information to generate context labels, and performs standardized characterization and magnetic state proxy conversion on voltage and current responses to generate pre-control standardized observation results, pre-control magnetic state risk quantities and voltage anomaly characterization. Then, it implements restricted diagnostic control actions, and combines the differences in multi-source responses before and after the control actions with the network real anomaly template responses and measurement distortion template responses in the template library to generate observation confidence results and controlled object risk state results, so as to determine the formal control path label and control level.

The application is suitable for the technical field of multi-level topology harmonic suppression and four-quadrant feedback control, and provides a multi-level topology harmonic suppression and four-quadrant feedback integrated control system and method, which comprises the following steps: S1, system initialization, input parameters, and loading preset parameters; S2, real-time calculation of output voltage harmonic distortion rate THD through fast Fourier transform, harmonic analysis, if the harmonic analysis is greater than 5%, the adaptive harmonic elimination algorithm is activated, and a compensation voltage waveform is generated; S3, separation of active / reactive components through Park transformation, judgment of energy flow direction, and four-quadrant mode switching; S4, the compensation voltage is superimposed on the modulation wave through the improved SVPWM, and then four-quadrant feedback control is carried out; S5, IGBT junction temperature, DC bus ripple, and harmonic spectrum are collected, power grid voltage fluctuation is predicted based on LSTM, and the carrier frequency is dynamically adjusted. The scheme has good harmonic suppression effect, high energy efficiency improvement, fast dynamic response, low maintenance cost, and strong environmental adaptability.

The application belongs to the technical field of flow-sensitive harmonic elimination devices, and particularly relates to a one-time neutral point access type flow-sensitive harmonic elimination device, which comprises a unit composed of PTC thermistors and PPTC thermistors in series, and then connected in parallel with a thin film capacitor and a pressure sensitive resistor, the unit is connected through N series to form a main circuit, the main circuit is connected with a PT one-time neutral point through a wire and the end is grounded; the device further comprises a wiring terminal, a base, a shell, a circuit board and filling glue, the wiring terminal is fixedly connected with the PT one-time neutral point through a screw, the base is fixed on a grounding row, the shell wraps the circuit board, the filling glue is filled in the shell, and the circuit board is integrated with the PTC thermistors, the PPTC thermistors, the thin film capacitor and the pressure sensitive resistor.

The utility model discloses a bus low residual voltage full frequency limit harmonic PT cabinet control system relates to low voltage circuit protection technical field, including the isolation handcart, high voltage current -limiting fuse and voltage transformer, the positive pole of high voltage current -limiting fuse is connected with low voltage power grid bus, through the active current -limiting harmonic eliminator and microcomputer secondary harmonic eliminator of setting, wherein the primary harmonic elimination of active current -limiting harmonic eliminator can eliminate high frequency resonance voltage, and microcomputer secondary harmonic eliminator can effectively eliminate low frequency resonance voltage, so can realize full frequency limit harmonic function, the resonance elimination and protection effect of this control system to low voltage circuit has been improved to the maximum degree to the active current -limiting harmonic eliminator thermosensitive type harmonic elimination module's resistance value is kiloohm level when normal work, and voltage transformer primary winding's resistance value is megaohm level when normal work, therefore will not produce the influence to each performance of voltage transformer.

The application discloses an electromagnetic voltage transformer current-limiting and resonance-eliminating device based on PTC characteristics and an optimization method thereof, and relates to the technical field of power protection. The device comprises the following steps: adopting donor doping, acceptor doping and glass phase modification to regulate and control barium titanate-based positive temperature coefficient ceramics to form a positive temperature coefficient core; forming a conductive electrode layer on the positive temperature coefficient core; connecting the positive temperature coefficient core in series according to the number of multiple pieces and in series according to the insulation packaging parameters, and then connecting the positive temperature coefficient core in series between a primary neutral point of a voltage transformer and the ground to form a current-limiting and resonance-eliminating device; and arranging the collected zero sequence voltage and neutral point current according to a unified sampling time mark to form a joint discrimination signal. The application can improve the identification accuracy among frequency resonance, fundamental frequency ferromagnetic resonance, arc grounding and single-phase grounding by first screening abnormal states in layers and then further distinguishing power frequency dominant abnormalities, so that the misjudgment and misoperation are reduced.

This application provides a harmonic elimination method and apparatus for modular multilevel converter high-voltage direct current (HVDC) transmission, comprising: constructing a current and voltage measurement matrix based on the topology and electrical parameters of an electromagnetic current transformer, its secondary system, an electromagnetic voltage transformer, and its secondary system in the HVDC transmission system; constructing an HVDC transmission impedance model including current and voltage measurement components based on the main circuit topology of the HVDC transmission system and the current and voltage measurement matrix; analyzing the HVDC transmission impedance model under preset operating conditions to obtain the impedance matrix of the current and voltage measurement components; and determining the resonant frequency of the HVDC transmission using the impedance matrix of the current and voltage measurement components to perform harmonic elimination. This application can analyze the mismatch effects caused by the measurement components of the current transformer (CT) and its secondary system, and the current transformer (PT) and its secondary system, respectively, determine the system resonant frequency, and eliminate the resonance effect.

The application discloses an IPOS-DAB non-communication switch harmonic elimination control method, which comprises the following steps: firstly, collecting input side voltage, extracting the DC component and the harmonic component of double switch frequency of the voltage, and extracting the amplitude and phase of the total harmonic component of double switch frequency; calculating the harmonic component of double switch frequency of the common point voltage generated by the self module; subtracting the self module harmonic component from the total harmonic component to obtain the sum of other module components; adjusting the phase of the self module harmonic component to be opposite to the phase of the sum of other module harmonic components, so that the total amount of switch frequency harmonics is minimum. On the basis of the IPOS-DAB converter topology, by analyzing the harmonic component of the switch frequency, only certain voltage signals need to be collected, the PWM phase of the self module is closed-loop adjusted, and any communication signal is not needed, so that the sum of the twice switch harmonic vectors of each module is zero, the true modularization is achieved, namely, plug and play, the total voltage and current harmonics are reduced, and the filter capacity is reduced.

The application relates to a radio frequency transceiver circuit, a communication device and a wireless communication method, wherein the radio frequency transceiver circuit comprises a signal transmitting module, a signal receiving module and a harmonic elimination module, the harmonic elimination module is connected with the signal transmitting module and the signal receiving module; wherein the signal transmitting module is configured to transmit a first signal; the signal receiving module is configured to receive a second signal through the harmonic elimination module, wherein the second signal transmitted to the harmonic elimination module comprises a received signal from an antenna and a harmonic interference signal leaked from a transmitting link of the first signal to a receiving link of the second signal; the signal transmitting module is further configured to delay a time length and output an anti-interference signal to the harmonic elimination module according to the time length, so that the anti-interference signal and the harmonic interference signal are superimposed in the harmonic elimination module, and the harmonic interference signal is eliminated.

The application discloses a cable connecting piece applied to a harmonic eliminator, relates to the technical field of harmonic elimination equipment, and comprises a wire connecting shaft arranged on the harmonic eliminator, the wire connecting shaft and a wire connecting post on the harmonic eliminator can conduct electricity to each other, a plurality of wire connecting stations are arranged on the wire connecting shaft, the wire connecting stations are used for sleeving conductive terminals, and the outer diameters of the plurality of wire connecting stations gradually increase from one end of the wire connecting shaft to the other end of the wire connecting shaft. The application has the effect of improving the adaptability between the harmonic eliminator and conductive terminals of different specifications.