3592 results about "AC - Alternating current" patented technology

The invention discloses an SLCC control method and system based on similar network type SVF assistance, and the method comprises the steps: generating a first SVF voltage instruction value through an active outer ring and a reactive outer ring, processing the first SVF voltage instruction value through a voltage ring, and obtaining a fundamental frequency reactive compensation current instruction value; processing the LCC output current by using a multi-synchronous rotation coordinate method to obtain a harmonic compensation current reference value; and superposing the fundamental frequency reactive compensation current instruction value and the harmonic compensation current reference value, obtaining a second SVF voltage instruction value in combination with a current inner loop controller, and processing the second SVF voltage instruction value by using a voltage-sharing control strategy and a carrier phase-shifting modulation strategy to obtain a switching signal for controlling the SVF. According to the method, the dependence of the SVF on an alternating current system is reduced, stable and independent operation of the SVF in the SLCC by virtue of the self regulation capability is favorably realized, and the operation reliability and stability of the SLCC are improved.

The invention relates to the technical field of active damping control, and discloses a bidirectional DC-DC power supply active damping control system and method, and the system comprises a front-end AC input rectification module, an LLC resonant circuit, and a Buck converter module: the front-end AC input rectification module is used for converting an AC input voltage into a DC voltage; the LLC resonance circuit is used for inverting the rectified direct current voltage into alternating current with a set frequency and transmitting the alternating current to a secondary side through a transformer; and the Buck converter module is used for rectifying an alternating current signal and adjusting the alternating current signal into a required direct current output voltage, and further comprises an LC filter and an active damping control module. By adopting the active damping control method, the resonance peak caused by the LC filter can be effectively suppressed without additionally adding a physical resistor, so that the fluctuation of the output voltage is limited. According to the control strategy, the problems of power loss and heating caused by a traditional passive damping method are avoided, and the energy efficiency of the system is remarkably improved.

The invention provides an alternating-current fault ride-through control method of a direct-current sending-out system and storage equipment thereof. The method comprises the steps that the operation condition of a wind power flexible direct-current system is monitored in real time; when it is detected that the direct current side voltage of the wind power flexible direct current system is larger than a set threshold value at the receiving end converter station, a direct current side energy consumption device of the flexible direct current system is started to dissipate surplus power; when an alternating current fault is detected at the sending end converter station based on the direct current side voltage, the sending end converter station is switched to a current limiting mode, a fan and a power transmission system of the wind power flexible direct current system are controlled, and surplus power is dissipated again through an unloading circuit; when the AC voltage recovers, the sending-end converter station is adjusted back to a normal mode; and power transmission of the wind power flexible direct current system is recovered. According to the invention, on the basis of the operation condition of the receiving-end and sending-end converter station direct-current voltage monitoring system, the energy consumption device, the fan, the power transmission system and other links are used for cooperative control, power can be balanced, equipment can be protected, and the system stability can be enhanced.

A power converter configured to be connected to three or more voltage parts, includes three or more power-conversion circuitries to be connected to respective ones of the three or more voltage parts, and a multi-port transformer connected to the three or more power-conversion circuitries at respectively different ports. The three or more voltage parts include a vehicle drive battery and a plurality of alternating-current (AC) voltage parts. Each of the plurality of AC voltage parts is configured to provide at least one of power input to a multi-port transformer side and power output from the multi-port transformer side.

The invention discloses a decoupling control method and system for a matrix motor with harmonic suppression capability, and belongs to the technical field of motor driving systems, and the method comprises the steps: building a matrix motor current loop mathematical model which considers a DC disturbance term and an AC disturbance term at the same time; based on the matrix motor current loop mathematical model, establishing a self-adaptive quasi-resonance extended state observer which simultaneously considers direct current disturbance observation and alternating current disturbance observation and performs self-adaptive adjustment on control parameters; the direct current and alternating current lumped disturbance of a matrix motor current loop is observed in real time through an adaptive quasi-resonance extended state observer; compensating the observed direct current and alternating current lumped disturbance in a forward controller of the current loop and obtaining a voltage control quantity; and controlling the matrix motor through a voltage vector space transformation and SVPWM modulation method according to the voltage control quantity. The method is improved and optimized based on an existing matrix motor vector control system, and the system does not need to be modified on a large scale.

The invention discloses a submarine cable detection method and device based on quantum magnetometers, the device comprises a multi-frequency signal generating device and a quantum magnetic field sensing device, and the quantum magnetic field sensing device comprises a first quantum magnetometer, a second quantum magnetometer and a signal processing module; according to the method, two quantum magnetometers which are horizontally installed are used for detecting the ratio of amplitude values of alternating magnetic fields generated by two equal-amplitude alternating currents with different frequencies in a submarine cable, and the distance relation between the two quantum magnetometers and the submarine cable is judged by comparing the ratio values detected by the two quantum magnetometers. And when the ratios detected by the two quantum magnetometers are equal, the position of the motion platform is the position of the submarine cable. The quantum magnetometer is used as a core sensor, so that the influence of posture change of the motion platform on detection data jitter is reduced, and the detection precision is improved; and a multi-frequency signal detection mode is adopted, so that the difficulty of extracting the characteristic magnetic field signal generated by the submarine cable to be detected from the total magnetic field is reduced.

A system includes: an alternating current (AC) to direct current (DC) converter (AC-DC converter), the AC-DC converter connectable to a line voltage; and a DC to DC converter (DC-DC converter) connected to the AC-DC converter, the DC-DC converter including: a high voltage buck-boost converter having a secondary side connectable to a high voltage battery; a low voltage buck-boost converter having a secondary side connectable to a low voltage battery; and one or more transformers having a primary side connected to the AC-DC converter, a secondary side connected to a primary side of the high voltage buck-boost converter, and a tertiary side connected to a primary side of the low voltage buck-boost converter.

The invention relates to the technical field of micro-grid control, and discloses an AC / DC micro-grid layered distributed control method and system, and the method comprises the steps: obtaining a DC voltage outputted by a distributed power supply in a DC micro-grid and an AC frequency outputted by a distributed power supply in an AC micro-grid, and carrying out the normalization processing; according to the voltage normalization value and the frequency normalization value, a finite time consistency algorithm is adopted to calculate a primary active power reference value of the interconnected converter; compensating the primary active power reference value according to a distributed secondary controller to obtain a secondary active power reference value; and generating a control signal of each interconnected converter according to the secondary active power reference value. Through hierarchical distributed control, the purposes that the total power sent by the direct current micro-grid and the alternating current micro-grid is proportionally distributed according to respective rated capacities and the active power transmitted by all the interconnected converters is proportionally distributed according to the transmission capacities are achieved, and the operation safety and stability of the alternating current and direct current micro-grid are effectively improved.

An integrated circuit for a power supply circuit that generates an output voltage from an AC voltage. The power supply circuit includes a full-wave rectifier circuit rectifying the AC voltage, a filter receiving the rectified voltage, an inductor receiving a voltage from the filter, and a transistor controlling an inductor current flowing through the inductor. The integrated circuit is configured to switch the transistor, and comprises: a terminal configured to receive a first voltage corresponding to a sum of a first current, which flows from the filter to a ground, and the inductor current; and a switching control circuit configured to turn on the transistor in response to the inductor current becoming smaller than a predetermined value, and turn off the transistor such that a peak value of the sum and the rectified voltage have waveforms that are in phase, and are proportional in amplitude, to each other.

The invention relates to the technical field of dual-mode Bluetooth chips, and discloses a radio-frequency signal gain control method and device for a low-power-consumption dual-mode Bluetooth chip, and the method comprises the steps: carrying out the RSSI detection and VSWR measurement of a radio-frequency signal of the low-power-consumption dual-mode Bluetooth chip, and obtaining a radio-frequency signal AC component and a radio-frequency signal DC component; performing bandwidth expansion on the alternating current component of the radio frequency signal, and performing power calibration on the direct current component of the radio frequency signal to obtain reconstructed radio frequency signal data; signal tracking ST time-frequency mapping is executed, the amplitude change rate, the phase deviation and the frequency drift of the radio frequency signal are extracted through a dynamic sampling mechanism, and nonlinear characteristic data are generated; and establishing a radio frequency parameter control network, executing AGC and ALC collaborative optimization calculation, generating a gain control sequence, and outputting radio frequency signal gain control parameters. According to the method, signal distortion and interference in the mode switching process are effectively reduced, and the reliability and stability of gain control are ensured.

A control system for an AC-DC converter includes a mixed-signal power controller and first and second gate drivers. The controller has a digital module and an analog module. The analog module has a current sensor generating a current sense voltage based on a sensed switch current. The digital module has a DC voltage sensor generating a DC sense voltage based on a DC bus voltage, and an AC voltage sensor generating an AC sense voltage and a binary polarity signal based on the AC voltage. The digital module induces the first gate driver to output first and second control signals for controlling a high-side switch and a low-side switch of a current shaping half-bridge based on first and second clock signals and the comparator voltage, such that an inductor current flowing through an inductor is proportional to a current command value.

The invention provides an ultrasonic transceiving device and a control method thereof. The ultrasonic wave transmitting and receiving device comprises a plurality of coupled ultrasonic wave transmitting and receiving units. Each ultrasonic wave transceiving unit comprises a plurality of ultrasonic wave oscillators; the driving bias circuit is coupled to the plurality of ultrasonic oscillators, and the driving bias circuit is used for receiving alternating current voltage; and a switching circuit coupled to the driving bias circuit, the switching circuit having a plurality of switching paths, the plurality of switching paths corresponding to a plurality of impedance values or a plurality of inductance values, the switching circuit is used for switching a system driving signal to pass through one of the switching paths according to a mode selection signal to serve as the alternating voltage and transmitting the alternating voltage to the driving bias circuit.

The present invention discloses a method and device for simultaneously measuring the bending vibration and torsional vibration of a rotating machinery shaft. The gear disk is installed on the shaft to be measured, and the gear disk is driven to rotate by the shaft to be measured. An alternating voltage signal is output by the eddy current sensor and converted into a digital signal by the software part, so as to obtain the original vibration signal. The maximum value finding method is used twice to extract the bending vibration and torsional vibration of the shaft. Through the above method, the simultaneous measurement of the torsional vibration and bending vibration of the shaft can be realized. The same set of sensors and instruments are used for the two types of vibration measurements, and the cost is relatively low.

The invention discloses a DC bias suppression method and system and a storage medium, and relates to the technical field of DC power transmission, and the method comprises the steps: building a switching function model according to the voltage of each phase of bridge arm of a three-phase bridge arm in a flexible DC converter valve; according to the switching function model, representing a bridge arm current as a direct current component and an alternating current fundamental frequency component of the bridge arm to obtain a bridge arm current component expression; according to the bridge arm current component expression, obtaining a voltage input quantity and a current input quantity of the converter valve transformer side in a steady state; and generating a DC bias suppression strategy of the flexible DC system according to the voltage input quantity and the current input quantity. By adopting the embodiment of the invention, the three-phase generation mechanism of the direct current bias can be analyzed from the current and voltage conditions of the three-phase bridge arm in the flexible direct current converter valve, the direct current component in the asymmetric scene can be identified in time, and the control of the flexible direct current system can be effectively inhibited and optimized from the transformer valve side.

The invention discloses a multi-phase-multi-phase direct-type AC-AC converter based on an MMC and a control method of the multi-phase-multi-phase direct-type AC-AC converter. The AC-AC converter provided by the invention comprises a modular multi-level converter and N single-phase three-winding transformers, the modularized multi-level converter comprises X phase units, the input side is provided with m ports and connected with a first alternating current system, and the output side is provided with N ports and connected with a second alternating current system. Each single-phase three-winding transformer comprises a first winding, a second winding and a third winding, the first windings of the N single-phase three-winding transformers are respectively connected with N phases of a second alternating current system, and the second windings are connected with N output side ports of an upper bridge arm of the modular multilevel converter; and the third winding is connected with N output side ports of the lower bridge arm of the modular multilevel converter. The AC-AC converter is based on the principle of synthesis of differential-mode and common-mode voltage components of MMC bridge arms, and is combined with a three-winding transformer with an anti-dotted terminal, so that the number of sub-modules of the M3C topology can be further reduced, and the AC-AC converter has good expansibility and is suitable for application scenes with various special requirements.

The present invention relates to a charging mode switching charging system (1) for energy stores to be charged, in particular on a new type of multicontact charging plug (2) for preferred use for charging electric vehicles on land, air and water. The new multicontact charging plug (2) is designed such that it can be handled more efficiently and easily than existing plugs in that during the charging process, it is possible to switch dynamically between direct (DC) and alternating current mode (AC). The invention aims to provide owners of electric vehicles with situation-related and efficient charging possibilities and promote the broad acceptance of electric vehicles by overcoming bottlenecks during processing at fast-charge points which are explicitly operated with direct current (DC), by user-controlled switching between DC and alternating current / three-phase alternating current (AC), which makes it possible to switch to other charging possibilities.

A display device is provided, which includes a display panel. The display panel includes a first substrate, a second substrate, a cholesteric liquid-crystal (ChLC) layer, and a driving circuit section. A plurality of first electrodes formed on the first substrate extend in a first direction. A plurality of second electrodes formed on the second substrate extend in a second direction different from the first direction. The ChLC layer is formed between the first substrate and the second substrate. The driving circuit section is configured to apply a plurality of alternating-current (AC) voltage pulses to pixel circuits at intersections between the first electrodes and the second electrodes. The driving circuit section is further configured to perform a full screen reset procedure to the display panel followed by a pulse-width modulation (PWM) scanning procedure to control cholesteric molecules within the pixel circuits to enter a focal conic state.

The invention provides a peak valley adjusting method and system for an alternating current charging pile of an electric vehicle, and belongs to the technical field of data processing. The adjusting method comprises the steps of obtaining data of a to-be-charged electric vehicle and historical data of an alternating current charging pile; calculating a charging urgency value of each to-be-charged electric vehicle; judging whether the charging urgency value of the electric vehicle is greater than a preset charging urgency value or not; if yes, adding to an emergency scheduling queue; otherwise, adding into a normal scheduling queue; taking minimization of the power demand change of the alternating current charging pile in the peak period and maximization of the utilization rate of the alternating current charging pile as targets, constructing a peak-valley adjustment model of the alternating current charging pile, and determining a target function and constraint conditions; under the constraint of the constraint condition, taking the minimum function value of the target function as a target, optimizing the peak-valley adjustment model, and outputting an optimal charging scheduling strategy; and according to the optimal charging scheduling strategy, scheduling the to-be-charged electric vehicle so as to perform peak-valley adjustment of the AC charging pile.

The invention relates to the technical field of high-voltage direct-current transmission, and discloses a reactive power support control method and system for a CLCC converter under an alternating-current fault, in order to fully explore the power support potential of the CLCC, the method comprises the following steps: firstly, starting from the forced commutation process of the CLCC during the fault period, analyzing that the trigger angle and the power have the multi-quadrant regulation and control capability; secondly, a direct current operable range and a trigger angle regulation and control range are determined; a power operation domain in the range is established; then, determining a trigger angle compensation amount and a control mode by taking no influence on active power transmitted to a receiving end alternating current system as a target; according to the method provided by the invention, the direct-current voltage and the direct-current transmission power of the inverter side during the alternating-current fault period can be kept unchanged, the voltage drop of the converter bus during the alternating-current fault period can be reduced, and the quick and stable recovery of the alternating-current voltage is facilitated.

A system includes: an alternating current (AC) to direct current (DC) converter (AC-DC converter) including a bulk capacitor, the AC-DC converter connectable to a line voltage; a DC to DC converter (DC-DC converter) connected to the AC-DC converter, the DC-DC converter including: one or more transformers having a secondary side connectable to a battery, and a bridge rectifier connected to the secondary side of the one or more transformers, the bridge rectifier including a bridge rectifier switch; and one or more controllers configured to control an operation of the bridge rectifier switch to control a voltage of the bulk capacitor.

The invention provides a single-phase four-quadrant rectifier IGBT open-circuit fault diagnosis method under multiple working conditions, and relates to the technical field of IGBT fault diagnosis. Historical data of alternating current side voltage, alternating current side current and direct current side voltage of the single-phase four-quadrant rectifier are obtained, and a total harmonic distortion rate threshold value, a direct current side voltage threshold value and an alternating current side current first threshold value are obtained. And constructing and training an IGBT open-circuit fault positioning identification model. Detecting the total harmonic distortion rate of the alternating-current side current of the single-phase four-quadrant rectifier in real time, if the total harmonic distortion rate exceeds a threshold value, entering fault positioning, collecting and calculating the average value of the direct-current side voltage and the alternating-current side current in the period, and judging the fault of the single-phase four-quadrant rectifier under the specific working condition according to the comparison of the average value and the threshold value. Or using an IGBT open-circuit fault positioning identification model to diagnose the fault; if the threshold value is not exceeded, the next period is continuously monitored. According to the invention, the IGBT fault diagnosis efficiency and accuracy of the single-phase four-quadrant rectifier are improved.

The invention discloses an AC voltage stabilizer dynamic regulation system based on an intelligent algorithm, and relates to the technical field of AC voltage stabilizers, and the system comprises a data collection module which is used for collecting a gate voltage waveform of an IGBT of an AC voltage stabilizer and an AC voltage instantaneous value of a power grid input end of the AC voltage stabilizer; the data processing module is used for determining a first Shannon entropy value of a rising edge and a second Shannon entropy value of a falling edge of the gate voltage according to the gate voltage waveform; determining an entropy change difference quantity between the rising edge and the falling edge according to the first Shannon entropy value and the second Shannon entropy value; determining a power grid input fluctuation quantity according to the AC voltage instantaneous value; if the power grid input fluctuation quantity is smaller than a fluctuation threshold value and the entropy change difference quantity is larger than a first preset difference threshold value, generating an inversion signal compensation waveform according to the gate voltage waveform; and injecting the inverted signal compensation waveform into a PWM modulator of the AC voltage stabilizer. According to the invention, the accuracy of identifying the real disturbance caused by the external power grid of the AC voltage stabilizer is improved.

A magnetic gradiometer can be used in systems or methods for nondestructive testing, even when the material being tested is weakly magnetic. The magnetic gradiometer can include a printed circuit board (PCB) comprising a first end and a second end separated by a base length; an excitation coil encircling at least a portion of the PCB and configured to deliver an alternating current (AC) to generate an excitation magnetic field; and a differential sensor. The differential sensor can include a reference magnetic tunneling junction in magnetic vortex state (vortex MTJ) sensor array at the first end to generate a voltage based on the excitation magnetic field; and a signal vortex MTJ sensor array at the second end to generate another voltage based on the excitation magnetic field due to a composition of the measurement target. The second end of the PCB can be oriented towards the measurement target.

An electric valve / door, and a control apparatus and method thereof are provided. The electric valve / door includes a control apparatus. The control apparatus includes an alternating current (AC) asynchronous motor, a transmission device, and a valve driver. The valve driver is connected to the AC asynchronous motor. The AC asynchronous motor is connected to the valve / door through the transmission device. The valve driver is configured to collect information of a real-time torque of the AC asynchronous motor or the valve / door during operation, and take a set torque of the valve driver as an input and the real-time torque as a feedback to immediately correct an output torque of the valve driver or a limit value of the output torque by using a proportional-integral-derivative (PID) control algorithm, to meet requirements for response speed and control precision of each stage in opening and closing processes of the valve / door.

The invention relates to the field of metal material nondestructive testing, and provides a non-ferromagnetic metal material surface profile reconstruction method based on a rotating alternating current electromagnetic field, which comprises the following steps of: determining a detection point array of a detection area, acquiring a vertical magnetic field signal z of the detection area by adopting a TMR magnetic sensing chip, and forming an initial Bz numerical matrix Bz0; performing bilateral filtering; obtaining a Bz numerical matrix Bz2 after morphological processing; obtaining a weighted Bz numerical matrix Bz3; a positive value matrix is formed, binarization processing is conducted on the positive value matrix, and a key numerical value matrix area Tkey containing crack related feature points is formed; calculating the center-of-mass coordinates of the disconnected independent areas, which are called nodes; on the basis of an improved Boruvka algorithm, new edge weight design is carried out on connecting edges between nodes, and a generated minimum spanning tree is effective representation of the surface profile of the bifurcated crack of the metal part.

The invention belongs to the cross technical field of biomedical engineering and nerve regulation technology. According to the brain-heart linkage transcranial strong alternating current stimulation feedback control method and system, heart rate variability characteristics are obtained according to electroencephalogram signals, electroencephalogram signal characteristics are obtained according to the electroencephalogram signals, and a dynamic coupling index is determined according to the electroencephalogram signals and electrocardiosignals; when the heart rate variability characteristic is greater than or equal to a corresponding heart rate characteristic baseline threshold value, the electroencephalogram signal characteristic is greater than or equal to a corresponding electroencephalogram characteristic baseline threshold value, and the dynamic coupling index is greater than or equal to a set threshold value, judging that the emotional disorder is improved, and keeping the intensity of the stimulation current unchanged; otherwise, increasing the intensity of the stimulation current to a set threshold value until the emotional disorder is improved. Through combined calculation of the electroencephalogram signals and the electrocardiosignals, dynamic monitoring and accurate evaluation of the process of treating the emotional disorder through transcranial strong alternating current stimulation are achieved, and the accuracy of electrical stimulation is guaranteed.

The present invention provides a method of inhibiting the growth of proliferating cells or viruses in living tissue, the method comprising: applying mid-level frequency AC current electromagnetic signals to the living tissue with a transducer comprising a magnetically conductive material passing through a conduction ring energized by an electrical signal to create the mid-level frequency AC current electromagnetic signals within the living tissue; wherein the mid-level frequency AC current electromagnetic signals have a frequency in the range of about 50 kHz to about 300 kHz and are produced with an AC voltage generator; and circulating fluid in the living tissue provide a secondary coil for the transmission of the mid-level frequency AC current electromagnetic signals.

The invention provides a broadband electric field sensor, an electric field sensor assembly and an electric field detection method.The broadband electric field sensor comprises a substrate, at least one dynamic induction electrode and at least one static induction electrode, the substrate comprises an entity area and a concave area, and the dynamic induction electrodes and the static induction electrodes are arranged at intervals; one part of the dynamic induction electrode is attached to the entity area, the other part of the dynamic induction electrode is located on the concave area, one part of the static induction electrode is attached to the entity area, the other part of the static induction electrode is located on the concave area, and the dynamic induction electrode obtains at least one direct current signal of a current electric field according to an excitation signal; the static induction electrode obtains at least one alternating current signal of the current electric field at least according to charges induced in the current electric field. The direct current signal and the alternating current signal can be obtained at the same time, good detection of a direct current electric field and an alternating current electric field is achieved, the sensitive degree of electric field detection is improved, and the detection frequency band of the electric field sensor is widened.

The embodiment of the invention provides a video monitoring transmission method and device based on dual-channel communication and selective encryption, and the method and device achieve the efficient transmission of data through building two independent channels, namely, a video data transmission channel and a control signaling channel. A device unique identifier and a key management mechanism based on a hardware security module are innovatively adopted, key frames in a video stream are selectively encrypted, and only a direct current coefficient representing overall brightness and an alternating current coefficient of detail information are encrypted and protected. Meanwhile, an intelligent load monitoring and sleep awakening mechanism is introduced, and the working state of the equipment is dynamically adjusted based on a video watching request, image change and a human body induction signal. According to the method, the system energy efficiency is remarkably improved while the data security is guaranteed, and a reliable technical scheme is provided for the field of video monitoring.

The invention discloses a magnetofluid type silicon controlled rectifier radiator and a heat dissipation control method thereof. The radiator comprises a silicon controlled rectifier, a magnetic fluid chamber is attached to the outer side of the silicon controlled rectifier, the magnetic pole array is installed in the magnetic fluid chamber, and cooling fins are assembled outside the magnetic fluid chamber. When alternating current is introduced into the cavity where the magnetic fluid liquid chamber is located, the alternating current and the magnetic field interact to generate Lorentz force, the Lorentz force drives the magnetic fluid to form directional eddy current so as to achieve convective heat exchange on the silicon controlled rectifier, and heat absorbed by the magnetic fluid and air are subjected to heat exchange through the cooling fins. Junction temperature out-of-control caused by local hot spots of the silicon controlled rectifier can be solved, secondary damage of mechanical vibration of a heat dissipation system to welding spots is eliminated, and the highest junction temperature area of the silicon controlled rectifier is focused and cooled according to needs.