353 results about "Active filter" patented technology

The invention provides an intelligent harmonic dynamic compensation method and system for a data center. According to the method, server heat source surface temperature field distribution is monitored in real time through a distributed optical fiber temperature measurement array, and a dynamic impedance spectrum is generated; when the temperature gradient exceeds the flash evaporation critical value of the fluorinated cooling liquid, an active filter is activated to carry out dynamic impedance matching compensation on high-frequency harmonic current in the liquid cooling tank cabinet, and a pulse width modulation control signal of a circulating pump is generated; the compensation power of the filter and the turbulence intensity of the cooling liquid are synchronously adjusted by analyzing the coupling relation between the flowing vortex intensity of the cooling liquid and the dielectric polarization loss; when phase mismatch of a temperature field is caused by heat dissipation of multiple heat sources, a multi-band compensation strategy is reconstructed by utilizing frequency domain characteristics of a pulse width modulation signal and a compensation power historical value, and a cooling liquid branch flow distribution ratio and a filter frequency response curve are cooperatively adjusted. According to the technical scheme, the thermal stability and the electrical safety of the data center cooling machine room are improved.

The invention discloses a main power grid short-time load prediction method using a hybrid active filter, and particularly relates to the technical field of load prediction. The method comprises the following steps: acquiring active control parameters and passive branch parameters of a hybrid active filter, combining a real-time load fluctuation signal of a main power grid, extracting harmonic suppression characteristics and phase distortion characteristics, and analyzing and generating a time scale compensation factor through a dynamic coupling effect; and constructing a phase correction model based on the transient harmonic residual component and the time scale compensation factor, and performing frequency domain and time domain combined reconstruction on the real-time load fluctuation signal to obtain a corrected load fluctuation characteristic sequence. A short-time load prediction model is calibrated through a collaborative mapping relation, a load power prediction value of a main power grid in a future preset time window is output, a secondary high-frequency interference signal generated by real load fluctuation and filter self-resonance is effectively distinguished, and the problem of coupling interference of harmonic residual components on the load prediction model in a power grid impedance sudden change scene is solved.

The invention relates to the technical field of wireless communication networks, and provides a low-channel electroencephalogram amplification circuit and brain-computer interface equipment oriented to an after-ear electroencephalogram signal, and the low-channel electroencephalogram amplification circuit comprises a dry electrode sensing module which is used for collecting an electroencephalogram signal; the front active amplification module comprises an operational amplifier circuit with high input impedance; the anti-aliasing filtering module is formed by cascading a multi-order passive filtering network and an active filtering circuit, is connected with the output end of the front active amplification module and is used for filtering high-frequency interference signals; the right leg driving feedback module comprises a programmable impedance adjusting circuit and a current limiting protection circuit, the right leg driving feedback module and the front active amplification module form a closed-loop feedback loop, and the output end of the right leg driving feedback module and the human body form a current loop through a protection resistor; the analog-to-digital conversion module adopts an integrated low-power-consumption analog front-end chip; a wireless transmission module; and the power supply management module provides independent power supply for the analog front-end chip, the operational amplifier circuit and the wireless transmission module.

The invention belongs to the technical field of power electronics, and relates to a T-type active EMI filter which comprises a detection link, an amplification link, an injection link and a multiplexing link. The detection link is composed of a detection resistor and a detection capacitor and is used for providing an additional flow path for common-mode current; the amplification link consists of a resistor and an operational amplifier and is used for reversely amplifying voltage at two ends of the detection resistor; the injection link is composed of injection resistors and used for converting voltage signals output by the operational amplifier into compensation current and injecting the compensation current into the multiplexing link, the multiplexing link is composed of a first capacitor and a second capacitor, branches are provided for common-mode current and the compensation current, and meanwhile system differential-mode noise is attenuated; moreover, the T-type three-capacitor structure enables the active suppression circuit to be composed of an operational amplifier and a pure resistor. Therefore, the overall size of the active filter is reduced, design and use are simpler and more convenient, stability is better, and common-mode noise and differential-mode noise can be attenuated powerfully.

The invention relates to the technical field of reactive power compensation of a power system, and discloses an active filter harmonic suppression and dynamic compensation system based on IGBT (Insulated Gate Bipolar Translator) multi-mode regulation and control. The system comprises a control module; the high-frequency harmonic detection module is electrically connected with the control module and is configured to detect a power grid harmonic signal in real time at a sampling rate of 200kHz and transmit the power grid harmonic signal to the control module; the IGBT gate driving compensation circuit is electrically connected with the control module and a preset IGBT module, and the control module dynamically adjusts the dead time and the switching frequency of the IGBT module through the IGBT gate driving compensation circuit; the IGBT junction temperature observer is electrically connected with the IGBT module and the control module and is configured to monitor the junction temperature of the IGBT module in real time and trigger the control module to start a derating protection mechanism when the junction temperature exceeds 125 DEG C; wherein the control module generates a PWM (Pulse Width Modulation) compensation waveform through a model prediction control algorithm unit based on a detection signal of the high-frequency harmonic detection module, so as to drive the IGBT module to execute harmonic compensation through the IGBT gate driving compensation circuit.

The invention discloses a method for generating an electrical system diagram. The method comprises the following steps: establishing a data table and a charting table based on an Excel program; arranging an electrical load information table according to the electrical equipment information, and filling in a load calculation table according to the electrical load information table; automatically calling, configuring and completing transformer parameters from the transformer parameter configuration table according to the transformer capacity and the compensation capacity through the composite nested function; establishing a feed cabinet table according to the number of the transformers, wherein the feed cabinet table comprises configuration of a reactive compensation cabinet, an active filter cabinet, a medium-voltage wire inlet cabinet and a contact cabinet; according to the equipment capacity and the installation power in the load calculation table, configuring outgoing line loop information through a composite nested function; and the CAD software automatically draws all transformer electrical system diagrams in the table by reading the drawing table. According to the method and the device, the problems of large calculation amount, non-uniform model selection, low efficiency and high error rate of a traditional CAD electrical system diagram in related technologies are solved.

The invention discloses a power distribution network harmonic suppression method and system, and the method comprises the steps: building an objective function with the minimum total harmonic distortion rate of nodes of a whole network, building a power flow constraint, a harmonic distortion rate constraint and an active filter device related constraint, and obtaining a power distribution network harmonic suppression model according to the objective function and constraint conditions. A distributed partially observable Markov decision process is established based on the MADDPG algorithm, and harmonic suppression is performed on the power distribution network based on the distributed partially observable Markov decision process by using the PRE-combined MADDPG algorithm, so that the problem of low sample efficiency of a reinforcement learning algorithm is effectively solved, the stability of a training process and the convergence speed of the algorithm are promoted, and the robustness of the power distribution network is improved. According to the method, the effectiveness of the finally obtained harmonic suppression strategy is ensured, based on a centralized training-distributed execution architecture, it can be ensured that a plurality of active filter devices can make a cooperative control strategy giving consideration to the harmonic problem of the whole power distribution network in real time only by means of distributed observation, and therefore efficient whole network harmonic cooperative governance is achieved.

The invention provides a hysteresis loop analysis method for a transformer no-load loss test, and belongs to the technical field of transformers. Exciting voltage and current signals are collected in a transformer no-load state, and an active filter is used for carrying out digital filtering processing to eliminate harmonic interference; a data corresponding relation between magnetic flux density and magnetic field intensity is established through a digital integration algorithm and a magnetic field intensity calculation formula to form original hysteresis data, the original hysteresis data is processed by using a hysteresis loop optimization model, a complete hysteresis loop curve is generated, and the hysteresis loop area is calculated. According to the hysteresis loop area, the hysteresis loss power density is calculated through the iron loss calculation function, the total value of the transformer no-load loss is obtained by combining the eddy current loss calculation result, and the technical problems that the hysteresis loop reconstruction precision is not high and the complex hysteresis phenomenon cannot be adapted in the transformer no-load loss test are solved.

The invention relates to an analog active EMI filter with a double-ring structure and a noise suppression verification method. The EMI filter comprises a direct-current power supply, an LISN circuit, a voltage detection circuit, an injection circuit, an amplification circuit and a switching power supply, the direct-current power supply, the LISN circuit, the voltage detection circuit, the injection circuit and the switching power supply are sequentially connected in parallel, the injection circuit comprises a voltage injection branch and a current injection branch connected with the voltage injection branch in parallel, the voltage injection branch and the current injection branch are used for voltage injection and current injection respectively, and the amplification circuit comprises a first anti-phase amplification branch and a second anti-phase amplification branch connected with the first anti-phase amplification branch in parallel. The first anti-phase amplification branch circuit is respectively connected with the voltage detection circuit and the current injection branch circuit to form a first annular structure, and the second anti-phase amplification branch circuit is respectively connected with the voltage detection circuit and the voltage injection branch circuit to form a second annular structure. Compared with the prior art, the method has the advantages of realizing an effective noise interference suppression effect and the like.

The invention discloses a multi-level pulse compensation type active EMI (Electro-Magnetic Interference) filter suitable for a multi-noise source switching power supply and a control method of the multi-level pulse compensation type active EMI filter. The invention provides a multi-level pulse compensation scheme based on switch behavior modeling, aiming at the problem of common-mode noise of adjacent rising edges and falling edges generated by a high-frequency switch in a multi-noise-source switching power supply. The time sequence delay and the edge slope of the compensation signal are calculated by analyzing the dv / dt characteristics in the switching-on and switching-off processes of the switching device, and accurate matching and offset with a noise source in phase and amplitude are achieved. Compensation control logic is realized by sharing a main control chip with a power circuit, and an additional controller and a high-precision sampling system are not needed; the self-adaptive tracking of the compensation amplitude is realized through the voltage following circuit; a multi-level compensation signal is output through the totem-pole circuit and injected into a common-mode path, and effective suppression of electromagnetic interference is achieved. The converter has the advantages of small size, low cost, simplicity and convenience in installation, high stability and the like, and is suitable for various multi-noise-source power electronic systems including a dual-active bridge converter, a phase-shifted full-bridge converter and an interleaving Buck converter.

The invention provides an electric energy quality treatment method, system and device based on a charging pile and a medium, and belongs to the technical field of charging piles, and the method is realized through the following steps: employing a mutual inductor to collect three-phase voltage / current; a common analog sampling and DSP processing circuit; harmonic / reactive power is identified based on the instantaneous reactive power theory, and a compensation instruction is generated; according to the compensation control instruction, driving an active filtering inverter circuit to inject compensation current into a power grid so as to reduce the total harmonic current content and improve the power factor; and the main controller generates charging state data according to the sampled voltage signal and current signal, and couples the data to an alternating current power line for transmission through the power line carrier communication module. The system guarantees the quality of the power grid, achieves the high efficiency and reliability of the operation of the charging pile, and gives consideration to the safety of the power grid and user experience.

The invention discloses a three-port high-voltage DC-DC converter with an active filtering bridge arm and a control method thereof, and relates to the field of power electronics. The invention aims to solve the problems that a multi-port topological structure needs a high-capacity magnetic element and the transmission efficiency is low. Two energy buffer bridge arms are connected in series; the energy transfer bridge arm is connected in parallel with the high-voltage-side and medium-voltage-side bridge arms; the low-voltage-side bridge arms are connected in parallel with two ends of the lower bridge arm; one ends of the high-pressure side valve group and the medium-pressure side valve group are connected with the energy transfer bridge arm, the other ends are respectively connected with the high-pressure side bridge arm and the medium-pressure side bridge arm, and two ends of the low-pressure side valve group are respectively connected with the low-pressure side bridge arm and the lower bridge arm. And the valve group is adjusted to be switched on or switched off, and the sum of output voltages of all half-bridge sub-modules is adjusted, so that the current flowing through the energy transfer bridge arm is trapezoidal wave, and charging or discharging is realized.

The invention discloses an intelligent power regulation system and method for a power distribution cabinet, and relates to the technical field of power regulation of the power distribution cabinet, and the method comprises the steps that a multi-source sensing unit carries out the early warning of harmonic overrun and local overheating risks in advance according to the collected three-phase current, three-phase voltage and harmonic components, and a temperature distribution matrix and external data generated by a thermal infrared imager; the edge prediction unit operates the LSTM-CNN-GRU hybrid neural network model to generate a future load prediction value, and stabilizes the voltage in advance; and the impedance self-adaptive execution unit enables the vibration value of the motor to be within a safety threshold value through the capacitor bank with the reconfigurable topology, the threshold value trigger type active filter and the tap switch controller according to the received optimization instruction.

A high-speed, low-noise laser signal detection apparatus, comprising a low-noise linear regulated power supply and a laser detection processing module. The low-noise linear regulated power supply (01-03) comprises an isolation unit (01), a voltage regulation and filtering unit (02), and a reference unit (03). The laser detection processing module (04-09) comprises a laser light signal detection input unit (05), a bias unit (04), a differential amplification unit (07), an active filtering unit (08), and an output interface unit (09). An output end of the voltage regulation and filtering unit (02) is connected to the reference unit (03) and the laser detection processing module (04-09). The reference unit (03) is connected to the bias unit (04) and is configured to provide a reference voltage to the bias unit (04). The bias unit (04) is configured to provide a bias voltage to the differential amplification unit (07). The differential amplification unit (07) comprises a multi-stage in-phase proportional differential amplification circuit, and the active filtering unit (08) comprises a multi-order active low-pass filter. According to the high-speed, low-noise laser signal detection apparatus, the detection bandwidth of a laser signal can be expanded, the signal-to-noise ratio of high-frequency pulse measurement can be reduced, and the anti-interference characteristics of a power supply can be improved.

The invention provides an analog correlation circuit of a synthetic aperture radiometer receiver, and relates to the technical field of weak signal detection and processing. The circuit comprises a high-stability power supply reference unit, a high-performance broadband multiplication unit, a low-noise amplification unit and a high-linearity differential active filtering unit, wherein a second-order differential active filter in the high-linearity differential active filtering unit is used for carrying out noise filtering and low-noise amplification on a low-noise amplifier output signal in a differential form, and a differential signal of which the bandwidth is matched with the variation range of the amplitude of a target radiation brightness temperature signal and the amplitude meets the subsequent analog-to-digital conversion requirement is output. The high-linearity differential active filtering unit designed by the invention is realized by a second-order differential active filter formed by connecting two differential active filters in series, a low-pass filter with the cut-off frequency as low as possible filters noise in a link to the maximum extent, only the bandwidth matched with signal change is reserved, the amplitude which is two times of that of a single-ended signal can be provided, and the filtering efficiency is improved. And the linearity and the signal-to-noise ratio performance are better.

The utility model relates to the field of active filtering devices, in particular to a low-energy-consumption active filtering device, which comprises a low-energy-consumption active filtering device body, an assembly for bearing and installing the active filtering device, and a fixing bolt which penetrates through the outer part of the low-energy-consumption active filtering device body and is used for connecting and installing a front packaging cover. The low-energy-consumption active filter device is provided with the inner filter frame, the built-in filter screen, the driving controller, the heat dissipation opening, the heat dissipation fan blades, the connecting rod and the miniature telescopic air pump, and the heat dissipation fan blades of the heat dissipation opening of the low-energy-consumption active filter device in an unstarted state are in a closed state, so that external dust can be prevented from entering the low-energy-consumption active filter body; after the low-energy-consumption active filter device is started, the driving controller controls the micro telescopic air pump to drive the connecting rod to stretch up and down, so that the connecting rod is linked with the heat dissipation fan blades to be unfolded in the heat dissipation openings, and the heat accumulated in the low-energy-consumption active filter body can be smoothly discharged through the heat dissipation openings in the two sides by opening the heat dissipation openings.

The utility model relates to the technical field of digital-to-analog conversion, and discloses a Delta-Sigma ADC data reading device, which comprises a power supply circuit, a photoelectric conversion circuit and a minimum system unit, one end of the power supply circuit is connected with an external direct-current power supply, and the other end of the power supply circuit is connected with the power supply end of the photoelectric conversion circuit and the power supply end of the minimum system unit; one end of the photoelectric conversion circuit is connected with an optical signal input end, and the other end of the photoelectric conversion circuit is connected with a signal end of the minimum system unit. According to the utility model, the minimum system unit with the built-in digital filter is adopted to replace a bit stream data conversion chip in the traditional scheme, so that the cost is reduced, and the area of a printed circuit board is saved; and the data interaction process between the active filter chip and the MCU is omitted, and the information transmission efficiency is improved.

The invention specifically discloses an ultrasonic guided wave edge real-time communication method and system based on an FPGA (Field Programmable Gate Array), and the method comprises the following steps: the FPGA of a guided wave communication transmitting circuit receives data needing to be transmitted, completes the data package construction and carrier modulation, and outputs a digital signal; after digital-to-analog conversion, a multi-stage power amplification circuit and a matching network circuit, the ultrasonic guided waves are transmitted to an excitation piezoelectric transducer, and the excitation piezoelectric transducer generates ultrasonic guided waves to be transmitted in a metal medium; the receiving piezoelectric transducer converts ultrasonic guided waves transmitted in a metal medium into piezoelectric signals, the piezoelectric signals sequentially pass through the active filter circuit, the variable gain amplification circuit and the analog-to-digital conversion circuit and are transmitted to the FPGA of the guided wave communication receiving circuit in the form of digital quantity, and the FPGA operates a demodulation algorithm to restore effective binary data. And the data is transmitted to other equipment. According to the technical scheme, the FPGA serves as a processing unit, high-frequency carrier modulation and real-time operation of a complex demodulation algorithm can be completed, and the high-speed communication requirement can be met.

A single-phase PWM rectifier direct-current side boost type active filter circuit control method based on a duty ratio feed-forward single current loop is characterized by comprising the following steps that inductive current of an active filter circuit is collected; collecting the direct current side current of the single-phase PWM rectifier; the method comprises the following steps: extracting a DC side current secondary pulsation component of a PWM rectifier as a reference current of an active filter circuit, performing high-pass filtering on the acquired inductive current of the active filter circuit to filter out a DC component, then subtracting the reference current, and enabling a deviation value to pass through a controller to obtain a current loop control component; the control component per unit of the current loop is added with the voltage control duty ratio Dv of the support capacitor of the active filter circuit for modulation to obtain a control signal of a corresponding switch tube. According to the method, a support capacitor voltage sampling circuit and a control loop of a traditional boost active filter circuit are omitted, the system hardware cost is reduced, the reliability is improved, and the control loop is simplified. The method is suitable for all active filter control which adopts a boost type active filter circuit for filtering on the direct current side, and applicable systems comprise single-phase rectification, single-phase inversion, multi-phase rectification, multi-phase inverters and the like.

Wireless circuitry can include a first filter circuit configured to output signals in a first frequency range, a second filter circuit configured to output signals in a second frequency range different than the first frequency range, and a signal combiner having a first input coupled to the first filter circuit and having a second input coupled to the second filter circuit. The wireless circuitry can further include a first switchable impedance matching circuit coupled between an antenna and the first filter circuit and a second switchable impedance matching circuit coupled between the antenna and the second filter circuit. The first and second filter circuits can be active filters such as lowpass-to-bandpass conversion filters operable in different frequency bands.

The invention discloses a cascaded active EMI filter and converter system based on element multiplexing. The cascaded active EMI filter comprises a feedforward current compensation EMI filter and a feedback current compensation EMI filter, the two filters share one power supply circuit and one current induction circuit and each comprise a voltage amplification circuit, a power amplification circuit and an output impedance circuit which are the same in structure. The input end of the current induction circuit is connected with positive and negative buses of the power electronic converter, and the output end is connected with the input end of the voltage amplification circuit; the output end of the voltage amplification circuit is connected with the input end of the power amplification circuit, and the output end of the power amplification circuit is connected with the output impedance; the output end of the output impedor is connected with the direct-current negative bus; the current sensing circuit is used for sensing common-mode current and outputting the same voltage signal to the voltage amplifying circuit; the voltage amplification circuit is used for amplifying the voltage signal and outputting the voltage signal to the power amplification circuit; the power amplification circuit outputs an amplified voltage signal to the output impedance circuit; the output impedance circuit is used for converting the amplified voltage signal into a current signal and offsetting the current signal with a system common-mode current; the EMI filter with the feedforward current compensation and the EMI filter with the feedback current compensation share the current induction circuit, the power supply circuit and the operational amplifier, low-frequency common-mode EMI of a converter system can be well restrained, the size of the cascaded active EMI filter is reduced, and the cost of the EMI filter is reduced.

The invention relates to the technology of power electronics and electric energy quality control, in particular to an energy storage type UPQC and switch state prediction control method based on improved model prediction control, which comprises a series active filter, a parallel active filter, a direct current bus, an energy storage system and a controller, according to the control method, an energy storage power and charge state dynamic equation is introduced into an MPC prediction model, and a multi-objective cost function is designed. And the controller predicts and evaluates the candidate switching vector in each sampling period based on a finite control set model predictive control strategy, and outputs an optimal switching state through value function optimization, thereby realizing collaborative optimization of electric energy quality management and energy storage energy management. According to the method, the dynamic response capability and compensation precision of the UPQC under the working conditions of voltage sag / sag, imbalance, harmonic waves and load fluctuation are remarkably improved, meanwhile, the energy storage utilization efficiency and the system stability are improved, and the method is suitable for a power distribution network with new energy high permeability and large load fluctuation.

To provide an active filter device in which an attenuation characteristic of a common mode noise filter can be effectively improved without large increase of the volume and the weight.SOLUTION: An active filter device includes a detection unit 29 that detects a common mode voltage, an inverting amplifier circuit 37 that inverts and amplifies the common mode voltage detected by the detection unit 29, and Y capacitors 21, 22, and an output voltage from the inverting amplifier circuit 37 is applied as a compensation voltage to the Y capacitors 21, 22. An amplifier unit 32 of the inverting amplifier circuit 37 includes an operational amplifier 35, and a current amplifier 40, and an output impedance compensation circuit 56 is provided that compensates a voltage drop associated with an increase of the output impedance of the amplifier unit, according to a voltage difference between input and output of the current amplifier.SELECTED DRAWING: Figure 2

The utility model discloses a small-capacity low-voltage active filtering device, which is suitable for being dispersedly installed on a low-voltage user side, a main circuit unit adopts a modular design and is connected in parallel on a bus between an alternating current power supply and a nonlinear load, a control mode of one main controller and multiple pairs is adopted, and a main controller is a control core of the whole parallel device. The auxiliary controller only needs to execute a command of the main controller without additional analysis and calculation, so that the plurality of main circuit units which are connected in parallel can be unified and coordinated, the main controller can realize closed-loop control according to a real-time detection result of the current detection unit, compensation current output by each main circuit unit is continuously corrected, and the compensation efficiency is improved. The harmonic or reactive current in the load current on the bus is offset, so that the current waveform of the power supply side is approximate to sine wave, the influence of the harmonic and the reactive current on other equipment and a relay protection device in a power grid is eliminated, the output consistency is good, the application is flexible, and the compensation effect is stable.

Electrical power converter (1) for converting an input voltage into an output voltage, comprising: -an input terminal (2) for obtaining the input voltage, the input terminal (2) having at least two lines (5a, 5b); -an output terminal (3) for providing the output voltage, the output terminal having at least two lines (6a-c); -a converter circuit (7) connected between the input terminal (2) and the output terminal (3), comprising at least one switching element (8a, 8b) and configured to convert the input voltage into the output voltage; -a sensing device (12) configured to detect a physical quantity based on a current flowing at a sensing terminal (13) which is one of the input and output terminals (2, 3) and to provide a sensing information (14) representing the physical quantity;- a controller (17) configured to control a switching operation of at least one switching element (8a, 8b) based on the detection information (14); - an amplifier circuit (19) configured to generate a compensation signal (20) based on the detection information (14); and - an injection circuit (21) configured to inject the compensation signal (20) into an injection terminal (22) which is one of the input and output terminals (2, 3) or to inject the compensation signal (20) into a ground plane (28) of the power converter (1); wherein the detection device (12), the amplifier circuit (19) and the injection circuit (21) form an active filter (23) to suppress the interference generated by the switching operation. Fig. 1;

The invention relates to a precise data acquisition device of a lightning arrester on-line monitoring system, and the device comprises a sensor unit which is used for obtaining a three-phase leakage current signal of a lightning arrester and a voltage signal of a corresponding phase in real time; a signal conditioning unit; a micro-current amplification circuit; a dynamic gain control circuit; a multi-stage active filter circuit; an electromagnetic shielding housing; a synchronous sampling unit; a data processing unit; a self-energy-taking power supply unit; and an intelligent communication unit. The beneficial effects are that through the high-linearity current transformer and the partial pressure type voltage sensor of the sensor unit, three-phase leakage current signals and corresponding-phase voltage signals of the lightning arrester can be accurately obtained; a micro-current amplification circuit, a dynamic gain control circuit and a multi-order active filter circuit in the signal conditioning unit work cooperatively, weak leakage current signals are effectively processed, the signal-to-noise ratio is improved, and it is ensured that the signals can still keep high precision in a complex electromagnetic environment.

Provided is an active filter device capable of effectively reducing common mode noise and differential mode noise and optimizing filter characteristics. The active filter device includes an inverting amplifier circuit 37 that inverts and amplifies a common mode voltage and a differential amplifier circuit 64 that differentially amplifies a differential mode voltage, and an output voltage of the inverting amplifier circuit 37 is applied as a common mode compensation voltage to Y capacitors 21, 22, an output of the differential amplifier circuit 64 obtained by amplifying a voltage of a positive-side power supply line 11 is applied as a differential mode compensation voltage to a negative-side X capacitor 42, and an output of the differential amplifier circuit 64 obtained by amplifying a voltage of a negative-side power supply line 12 is applied as a differential mode compensation voltage to a positive-side X capacitor 41.

Wireless circuitry can include a first filter circuit configured to output signals in a first frequency range, a second filter circuit configured to output signals in a second frequency range different than the first frequency range, and a signal combiner having a first input coupled to the first filter circuit and having a second input coupled to the second filter circuit. The wireless circuitry can further include a first switchable impedance matching circuit coupled between an antenna and the first filter circuit and a second switchable impedance matching circuit coupled between the antenna and the second filter circuit. The first and second filter circuits can be active filters such as lowpass-to-bandpass conversion filters operable in different frequency bands.

The invention relates to the field of power grid state evaluation, discloses a power grid state evaluation method and system based on a high-capacity high-voltage active filtering structure, and realizes breakthrough in the fields of economic quantification of harmonic suppression, dynamic risk evaluation, multi-party collaborative decision, data security and the like through interdisciplinary fusion. According to the method, the multi-dimensional data of the active filter is obtained, processing and analysis are carried out by utilizing advanced technologies such as quantum calculation, results such as a quantum risk thermodynamic diagram, an equipment health degree attenuation curve and a Nash equilibrium decision path are generated, and scientific decision support is provided for power grid enterprises, users and supervision organizations. Meanwhile, an anti-interference asset configuration table is coded into a photon orbital angular momentum state, data topology protection is achieved through an optical annular cavity, and a quantum anti-counterfeiting supervision report with anti-counterfeiting performance and traceability is generated.

The invention relates to the technical field of low-voltage direct-current power supply, and discloses a direct-current active filtering method and system based on a three-level topological connection low-voltage direct-current power supply system. Firstly, a three-level topological active filter is connected with the low-voltage direct-current power supply system in parallel, so that the voltage stress of a switching tube is reduced; reference voltages under different working conditions are dynamically generated through a preset working condition proportionality coefficient, the compensation capacitor voltage can be more accurately adjusted, the compensation precision is improved, a processing mode of firstly adopting a proportional resonance controller and then adopting a proportional controller is adopted, so that the active filter more effectively suppresses various ripple components, and finally, the active filter can be effectively controlled. The three-level topological active filter can drive the switching tube to be switched on and switched off according to different modulation results, the filter inductor is flexibly controlled to generate the compensation current, finally, the compensation current injected into the low-voltage direct-current power supply system can be more effectively subjected to ripple filtering, and the ripple suppression capacity in the system is remarkably improved.