266 results about "Overmodulation" patented technology

The invention discloses a micro-grid power control method, system and device based on fuzzy modulation and a storage medium, and relates to the technical field of intelligent grid integration of a photovoltaic system and a micro-grid, and the method comprises the steps: firstly obtaining the real-time power data of a photovoltaic system, carrying out the control processing through fuzzy logic, and calculating a reference instruction; according to the reference instruction, hysteresis time is dynamically adjusted through modulation hysteresis control, and an inverter switching signal is generated; converting direct current into alternating current based on the switching signal and a power switching device, injecting the alternating current into the micro-grid, calculating active and reactive power reference values, ensuring that the system operates according to a unit power factor, and giving active power to the reference value; according to the method, the power control precision and adaptability of the micro-grid are improved, excessive switching of the inverter is avoided, loss is reduced, the service life is prolonged, power matching and stable transmission are achieved, reactive loss is reduced, bus voltage is stabilized, harmonic waves can be reduced, the electric energy quality is improved, and efficient and stable operation of the micro-grid is guaranteed.

Aspects of the present disclosure provide an over-the-air (OTA) interferometer that enables redirecting, by a reconfigurable intelligent surface (RIS) to a destination, a signal that impinges the RIS at each of a plurality of time slots, thereby modulating the signal. The RIS is virtually divided into a plurality of RIS portions. In each time slot, phase components to be applied to the plurality of RIS portions are determined based on one or more phase values. The phase values may include an underlying phase related to redirecting a source signal, an additional phase related to data that an input operatively connected to the RIS aims to transmit to the destination by modulating the signal being redirected, and / or a further phase related to interference patterns that can help extract the data phase at the destination. The destination may demodulate the received signals based on the signal strength measurements.

The invention relates to the technical field of power cable data communication, in particular to a power line carrier communication system peak-to-average power ratio suppression method, which comprises the following steps: carrying out structure definition on modulated frequency domain data at a sending end, constructing a complete spectrum signal, and carrying out copying based on the complete spectrum signal to respectively obtain a processing signal and an original signal; training an LSTM auto-encoder model, and inputting the processing signal to the trained LSTM auto-encoder model to optimize the bit error rate and the peak-to-average ratio loss so as to generate a peak clipping signal; splicing the peak clipping signal with the original signal to form a new sending signal; a transmit signal is converted into a time domain signal based on an inverse fast Fourier transform. The method has the effect of improving the carrier communication quality and communication efficiency of the power line.

The invention discloses a converter grid following-grid construction control mode smooth switching method suitable for wide-range source-grid state change. The method comprises the following steps: constructing a phase-locked loop control loop, a power outer loop control loop and a current inner loop control loop of a grid following type converter based on constant power control; constructing a voltage control loop, a phase control loop and a voltage and current double-closed-loop control loop of the network construction type converter based on the virtual synchronous generator VSG; calculating real-time output active power P and reactive power Q of the converter; constructing a voltage phase synchronization loop switching control loop and a current instruction tracking loop, and realizing smooth switching of dq-axis current instruction values output by a power outer loop of a following network type and a voltage outer loop of a construction network type; and the output dq-axis current instruction value is transmitted to a current inner loop to generate a final voltage signal, and a PWM wave is output to the converter through a modulation link. According to the method, a voltage phase synchronous switching compensation mechanism is adopted, a voltage amplitude and a phase signal are synchronously corrected in the mode switching process, and smooth change of an inner ring current reference signal is achieved.

The invention discloses a low-harmonic high-voltage speed regulation system based on a multi-pulse phase-shifting transformer, and particularly relates to the field of power electronic technology and motor speed regulation, which is characterized in that the primary side of the multi-pulse phase-shifting transformer is in star connection, and N groups of windings on the secondary side are in extended delta connection, so that phase difference is realized; the multi-path low-voltage alternating current is converted into multi-path low-voltage alternating current and low-order harmonics are High voltage is output through cascade H-bridge topology series connection, and reliable conversion is guaranteed through rectification filtering inversion and device redundancy design; the motor control module collects signals through multiple sensors, and PWM drive signals are generated through a vector control algorithm and coordinate transformation. The harmonic detection and compensation module detects harmonic waves based on an FFT algorithm, and injects a reverse compensation component through a modulation strategy to offset the harmonic waves; and the auxiliary protection module integrally realizes low-harmonic and high-precision high-voltage motor speed regulation through multi-dimensional monitoring and hardware protection.

The embodiment of the invention discloses a multiplex type three-stage starting power generation controller, and relates to the technical field of aviation three-stage starting power generators. In the starting stage, an H-bridge inverter in the starting power generation controller provides single-phase alternating-current exciting current for a main exciter stator exciting winding through SPWM modulation so as to establish a pulsating magnetic field to provide exciting current for a main motor, and a three-phase full-bridge inverter provides armature current for a main motor stator armature winding through SVPWM modulation. In a power generation stage, an anti-parallel diode of the three-phase full-bridge inverter is used as a rectification circuit of the auxiliary exciter, and the H-bridge inverter adopts a PWM chopping mode to operate as an asymmetric half-bridge circuit. A power generation controller and a starting controller are integrated into a whole, and by changing the modulation mode of a hardware circuit, the control function of the three-stage starting generator at different stages can be realized by only one controller, so that the structure of the starting power generation controller is simplified, the system integration degree of the three-stage starting generator is improved, and the volume and the weight of the system are reduced.

The invention provides a flexible direct current converter valve system and a modulation method thereof. Based on a novel hybrid module series structure, target voltage modulation is carried out by controlling a switch device trigger pulse in stages through polarity distribution of modulation wave voltage and bridge arm current. And executing a four-stage pulse adjustment process in an inversion or rectification mode, and dynamically managing the removal and input time sequence of the improved half-bridge power module. According to the method, the trigger pulse is accurately regulated and controlled according to the real-time polarity and the transition state of the voltage and the current, and the problems of instantaneous overcurrent and local overheating of a switching device under the overload condition in the traditional bridge arm topology are avoided. Through staged logic control, the system maintains the stability of the modulation wave voltage, reduces the thermal stress accumulation of the device, improves the endurance capability of the converter valve under a complex working condition, does not need external current limiting intervention, and enhances the operation flexibility and reliability.

The invention discloses a photovoltaic air conditioner and a direct current component suppression method thereof, electronic equipment and a medium, and the suppression method comprises the steps: building a bus ripple detection circuit at the direct current side of a single-phase inverter, and obtaining a bus ripple sampling result; carrying out primary compensation on a direct current component, and generating a current for compensation based on the direct current bus voltage; subtracting the acquired actual grid-connected current to obtain a grid-connected current error value, compounding the grid-connected current error value with a power grid voltage feed-forward signal and a capacitance current feedback signal to generate a duty ratio signal, and driving an inverter in an SPWM (sinusoidal pulse width modulation) mode; carrying out secondary compensation on the direct current component, carrying out phase tracking on the voltage of the power grid through SOGI-PLL with FLL, and generating a phase-synchronous current modulation signal; and adding the compensation signal with the current difference to obtain a compensation signal, and adjusting the duty ratio of the inverter. According to the invention, the grid-connected direct-current component of the photovoltaic household air conditioner is effectively reduced.

An assembly and method are disclosed for generating and detecting a modulated pressure signature in a fluid transported to a subsurface injection zone. The assembly includes a pump, a pulsation dampener, and a pressure modulation device that oscillates pressure to produce a frequency-modulated signature in the fluid, resulting in an alternating current streaming potential (AC-SP) at the injection zone. The method includes recording modulated electromagnetic signals at an array of electromagnetic field receivers on a surface above the subsurface injection zone, processing the data to identify source frequency signals, and correlating these signals to image subsurface fluid or pressure distribution, enabling three-dimensional mapping of subsurface structures.

The invention discloses a chaos communication and perception integrated signal processing method and device and a communication system, and the method comprises the steps: segmenting an information bit sequence into a modulation bit sequence, an index bit sequence and a PPM bit sequence, and carrying out the processing of an initial signal vector through the combination of a pulse position modulation technology, according to the scheme, the frequency spectrum utilization rate is optimized through dual control of modulation bits and index bits, initial modulation signals are segmented according to PPM orders, signal vectors are generated, time domain offset is carried out on the signal vectors in combination with a shift matrix, the good self-correlation characteristic and the low cross-correlation characteristic of LFM signals are utilized, on the basis of an original DCSK-LFM modulation mode, the frequency spectrum utilization rate is improved, and the frequency spectrum utilization rate is improved. And in combination with pulse position modulation and index modulation, the same carrier can bear more information, so that the transmission rate when the method is applied to a JRC system and the overall performance of a communication system are improved.

The application provides a kind of FMCW laser radar signal processing method and system, method includes: the laser signal generated by laser is divided into measurement light signal and local light signal;Input measurement light signal to light modulator, modulate by modulated sine wave sweep signal;Amplify modulated measurement light signal, emit to the detection target by circulator, collimating mirror, receive reflected signal;Coupling with reflected signal, enhance the energy of signal light, carry out photoelectric signal conversion;Amplify converted electrical signal, carry out electrical mixing in mixer, output intermediate frequency signal;Low-pass filter processing is carried out to intermediate frequency signal;In signal processing system, intermediate frequency signal is converted into pulse square wave by high-speed comparator, carries out capacitance analog interpolation processing, measures intermediate frequency signal period, calculates intermediate frequency signal frequency value.The application solves the technical problem that the counting error of ±1 word leads to the period of to-be-measured intermediate frequency signal, the distance calculation precision of detection target is low.

The invention provides an open-winding permanent magnet synchronous motor predictive current control method based on hybrid pulse width modulation, and the method comprises the steps: calculating a reference voltage vector, dividing voltage vector sectors according to the reference voltage vector, and selecting a non-zero voltage vector and a zero voltage vector in each sector; according to the sector and range where the reference voltage vector is located, selecting a voltage vector which needs to be acted by the double inverters, and calculating the time when each inverter acts on the voltage vector by using a volt-second balance principle; if the action time of the selected voltage vector exceeds the control period, overmodulation processing is carried out, and the voltage vector time is redistributed; if the zero-sequence current is suppressed, the zero-sequence current and the zero-sequence voltage are suppressed by adjusting the action time of the zero-sequence voltage vector. The control performance of the open-winding permanent magnet synchronous motor can be improved, and the zero-sequence current of the open-winding permanent magnet synchronous motor can be suppressed.

A control system for an electric motor of an electrified vehicle includes an inverter of the electrified vehicle, the inverter comprising a set of switches and being configured to receive three pulse-width modulation (PWM) signals and to control the set of switches to generate an alternating current (AC) output voltage from a direct current (DC) link voltage provided by a battery system of the electrified vehicle, and a control system configured to determine a torque command for the electric motor, determine commanded d-axis and q-axis voltages based on the torque command, generate a trapezoidal wave modulating signal for carrier-based PWM based on the commanded d-axis and q-axis voltages, generate the three PWM signals by performing carrier-based PWM using the trapezoidal wave modulating signal, and control the electric motor using the AC output voltage generated by the inverter.

The application belongs to the technical field of power electronic control, and particularly relates to a kind of energy storage converter parallel control method and system.The method comprises: after Clark transformation, Park transformation of three-phase voltage signal and three-phase current signal output by inverter, active power and reactive power are calculated;Reference value of voltage loop and current loop is calculated, and prediction value is superimposed on current loop to obtain direct axis front end voltage and cross axis front end voltage, and then direct axis voltage and cross axis voltage are calculated;Direct axis voltage and cross axis voltage are subjected to SPWM modulation, and inverter bridge arm switch tube is driven to turn on and off to control inverter output.The prediction value superimposed in the application can quickly compensate the reference value required by current loop when load mutates, and then maintain the stability of voltage.

The invention relates to the technical field of multimode interference, and provides a central wavelength tunable multimode interference device which comprises an input waveguide region, a multimode interference region and an output waveguide region which are connected in sequence, the multimode interference region comprises a core layer, the core layer is made of a high-refractive-index material, and the output waveguide region is made of a high-refractive-index material. And a modulation electrode structure for modulating the refractive index of the core layer is arranged on the multimode interference region. The invention further provides a manufacturing method of the multimode interference device with the tunable central wavelength and a coherent modulator. Refractive index modulation is carried out on the core layer of the multi-mode interference area through the modulation electrode structure, in the multi-mode interference area, the effective refractive index directly determines the self-mapping point positions of different wavelengths, therefore, the effect of tunable central wavelength can be achieved through refractive index modulation, and through selection of different bias voltages, the tunable wavelength of the multi-mode interference area can be achieved. And the output effect of the optical power in the output waveguide is tuned.

An oxidation corrosion product thickness on-line measurement method based on a photoacoustic effect comprises the following steps: modulating laser with a specific frequency to irradiate on the CRUD surface of a fuel cladding, monitoring an acoustic wave signal emitted by the CRUD surface by using a piezoelectric sensor, and establishing an on-line conversion model of the acoustic wave signal and the CRUD thickness so as to obtain visual thickness real-time data. On the condition that the original environment of the CRUD is not damaged, online in-situ measurement is carried out on the thickness of the CRUD, and it is ensured that the real thickness of the CRUD in the growth environment can be accurately reflected by measurement data. Through the method, the dynamic growth behavior characteristics of the CRUD thickness can be obtained, so that more accurate monitoring and guidance are provided for safe operation and fuel management of a reactor.

The invention discloses a boost converter and a transient response circuit and a control method thereof, and relates to the technical field of switching power supplies, and the boost converter comprises a voltage detection circuit and a control circuit. The circuit comprises a voltage detection circuit and a control circuit, and the voltage detection circuit can monitor abnormal drop or overshoot of the output voltage in real time and immediately generate a level signal. The control circuit responds to the signal and provides a'lead 'or'lag' correction value for the feedback control circuit by modulating the reference voltage, so that the response delay of the system is effectively compressed, and the recovery process of the output voltage is accelerated. On the premise that the original bandwidth and phase margin of a main loop are not changed, the transient response speed is increased, the recovery process of a system is accelerated, and the contradiction that stability and fast transient response cannot be considered at the same time due to zero point limitation of a right half plane of a traditional boost converter is solved.

The application discloses a modulation and control method for improving short-time overload capacity of an ANPC topology. In view of the problem that the overload capacity improvement method of the existing grid-connected converter of the ANPC topology is high in cost and poor in universality, the application actively reduces the switching frequency, an operating parameter, at the software algorithm level, effectively reduces the output loss of the grid-connected converter in the overload operating state, and effectively improves the short-time overload operating capacity of the grid-connected converter by switching the modulation mode to effectively uniformly distribute the switching loss of each device without substantially increasing the cost and performance of the grid-connected converter.

The application discloses an online measurement method for the thickness of oxidation corrosion products based on the photoacoustic effect, which comprises the following steps: modulating laser irradiation of a specific frequency on the CRUD surface of a fuel cladding, monitoring the sound wave signals emitted by the CRUD surface by using a piezoelectric sensor, and establishing an online conversion model of the sound wave signals and the CRUD thickness, so that intuitive real-time thickness data can be obtained. The thickness of the CRUD is measured online and in situ without destroying the original environment of the CRUD, so that the measurement data can accurately reflect the real thickness of the CRUD in the growth environment. Through the method, the dynamic growth behavior characteristics of the CRUD thickness can be obtained, so that more accurate monitoring and guidance can be provided for the safe operation and fuel management of a reactor.

To provide a motor drive method capable of improving a maximum output of a motor even if a dead time is secured by driving a three-phase DC brushless motor by overmodulation PWM control with a modulation factor in a predetermined range exceeding 100% in a sensor-less manner.SOLUTION: A control circuit 4 outputs a pulse signal having a duty ratio of 0% to an inverter circuit 2 when a predetermined minimum value is input as a modulation signal, outputs a pulse signal having a duty ratio of 100% to the inverter circuit 2 when a predetermined maximum value is input as the modulation signal, and outputs a pulse signal having a duty ratio of 100% to the inverter circuit 2 when an overmodulation signal having a maximum modulation degree, which is a ratio of a maximum value of the modulation signal relative to the predetermined maximum value, larger than 100% is input as the modulation signal and an overmodulation state occurs in which an instantaneous value of the modulation signal becomes larger than the predetermined maximum value.SELECTED DRAWING: Figure 30

The invention discloses a modulation and control method for improving the short-time overload capacity of ANPC topology. Aiming at the problems of high cost and poor universality of the existing method for improving the overload capacity of the grid-connected converter of the ANPC topology, the method disclosed by the invention effectively reduces the output loss of the grid-connected converter in an overload operation state by actively reducing an operation parameter, namely switching frequency, on a software algorithm level; and the switching loss of each device is effectively and uniformly switched through a modulation mode, so that the short-time overload operation capability of the grid-connected converter is effectively improved on the premise that the cost and the performance of the grid-connected converter are not greatly improved.

The invention discloses a motor linear overmodulation method and device, a vehicle and a storage medium, and the method comprises the steps: obtaining a reference voltage component and a DC bus voltage of a motor, and obtaining a reference voltage amplitude and a reference voltage phase angle according to the reference voltage component; a modulation coefficient is obtained according to the reference voltage amplitude and the direct-current bus voltage, the working area of the motor is judged according to the modulation coefficient, and the working area is divided into a linear modulation area, an overmodulation I area and an overmodulation II area according to the modulation coefficient; and when the working area is the overmodulation II area, obtaining a dynamic weight coefficient according to the reference voltage phase angle, and controlling the motor according to the dynamic weight coefficient. Therefore, when the working area of the motor is the overmodulation II area, the motor is controlled according to the dynamic weight coefficient obtained by the voltage phase angle, so that the voltage jump of the overmodulation II area is eliminated, the power performance of the electric vehicle driving system is improved to the maximum extent, and meanwhile, the output smoothness is ensured.

The class AB amplifier device includes an input chopper switch circuit that performs a chopping operation in synchronization with a first and second chopper clock signal, and outputs first and second modulated signals obtained by modulating the first and second differential input signals to a first and second node; an input amplifier circuit that receives the first and second modulated signals via the first and second nodes, and outputs a differential amplified signal obtained by amplifying the first and second modulated signals; an output chopper switch circuit that receives the differential amplified signal, performs a chopping operation in synchronization with the first and second chopper clock signals, and modulates the differential amplified signal to output a demodulated signal demodulated to the frequency band of the first and second differential input signals; and an output amplifier circuit that outputs a first output signal obtained by amplifying the demodulated signal.

The invention provides a communication method and device, and the method comprises the steps: generating an auxiliary synchronization signal which is a signal obtained based on a first sequence; the waveform of the auxiliary synchronization signal is a single carrier waveform; and sending the secondary synchronization signal. Wherein the first sequence is determined according to the second sequence, the lengths of the first sequence and the second sequence are L, and an element d (m) of the second sequence and an element x (n) of the first sequence meet the following conditions: m = (n + c) modL, 0 < = n < L, 0 < = m < L, and d (m) = 0, 1, 2 or 3; c is p * ID. In the method, the first sequence satisfying the form has low cross correlation after being modulated, and the waveform of the auxiliary synchronization signal is a single carrier waveform, so that the PAPR performance of the auxiliary synchronization signal can be improved, the PAPR of the auxiliary synchronization signal can be reduced, and the coverage range of the auxiliary synchronization signal can be improved.

The invention relates to the technical field of soft start control of resonant converters, in particular to a soft start control method of a CLLC resonant converter with a short-circuit protection function, which comprises the following steps: S1, establishing a time domain model of the CLLC resonant converter; s2, calculating an output frequency based on the actual output of the CLLC resonant converter through a PI controller; s3, building a gain-minimum frequency curve based on the time domain model of the CLLC resonant converter, and obtaining the minimum switching frequency based on the voltage gain of the CLLC resonant converter; s4, determining the switching frequency based on the output frequency and the minimum switching frequency; and S5, a driving signal is calculated based on the switching frequency through a PWM modulator, and the CLLC resonant converter is driven, so that the peak resonance current of the CLLC resonant converter does not exceed a set value. According to the invention, the peak resonance current of the CLLC resonant converter can be limited not to exceed the set value, and the peak current control is realized in the starting and operating processes, so that the peak of the resonance current can be accurately limited under all working conditions.

The invention discloses an intelligent chord generation method and system and a storage medium. The method comprises the following steps: acquiring musical scales, chord types and root tone information selected by a user through a physical encoder and chord type shortcut keys; according to musical scales, chord types and root tone information set by a user, modulating the frequency of a waveform through a modulator, and generating corresponding chord tone characteristics based on an FM synthesizer principle; obtaining and correcting the chord timbre characteristics based on a preset chord rule to obtain a target chord; and obtaining and carrying out cooperative processing on the target chord and the Bass sound part according to the Bass sound part parameters, adjusting the arrangement rule of the chord and the Bass sound part in real time, and realizing linkage playing of the chord and the Bass sound part. Information such as user scales is obtained through a physical encoder and chord shortcut keys, chord timbre characteristics are generated through a modulator and an FM synthesizer, then the timbre characteristics are corrected, and real-time linkage playing is achieved in combination with Bass sound part cooperative processing.

The present invention relates to the technical field of wireless communications, and provides a communication circuit, method, apparatus, and system. The communication circuit comprises a modulation element, an energy convergence network, and a second resonant network. The modulation element disperses energy of a first microwave signal at a first frequency at a first port and transmits same to an energy network via a second port. The energy convergence network converges the dispersed energy to obtain a second microwave signal. The second resonant network performs secondary frequency selection on the second microwave signal and generates an oscillation signal at a second resonant frequency, and transmits the oscillation signal to the modulation element via a third port to mix with the first microwave signal, thereby obtaining a frequency-converted signal at a second frequency. The present invention provides multiple signal transmission paths from the energy convergence network to the second resonant network that bypass the modulation element, thereby reducing the loss of the second microwave signal and acquiring a frequency-converted signal with increased power, and correspondingly lowering the transmit power requirements of a transceiver apparatus and the microwave drive power threshold of the communication circuit.

A control system for an electric motor of an electrified vehicle includes an inverter of the electrified vehicle, the inverter comprising a set of switches and being configured to receive three pulse-width modulation (PWM) signals and to control the set of switches to generate an alternating current (AC) output voltage from a direct current (DC) link voltage provided by a battery system of the electrified vehicle, and a control system configured to determine a torque command for the electric motor, determine commanded d-axis and q-axis voltages based on the torque command, generate a rectangular wave modulating signal for carrier-based PWM based on the commanded d-axis and q-axis voltages, generate the three PWM signals by performing carrier-based PWM using the rectangular wave modulating signal, and control the electric motor using the AC output voltage generated by the inverter.

a conversion unit that calculates a duty cycle corresponding to each of the plurality of pulse-width modulated signals in dependence on the instruction; a gain unit that selects a gain that produces a linear relationship between the required voltage of the pulse-width modulated signal and the voltage achieved by the plurality of pulse-width modulated signals, even when the required voltage of the pulse-width modulated signal is in an overmodulation region, and applies the gain to each of the duty cycles to produce an adjusted duty cycle; and an output unit that outputs the adjusted duty cycle for generating the plurality of pulse-width modulated signals.

A method (100) for determining a power dissipation value of an electronic power circuit during an electrical period of a modulated control signal is disclosed, comprising: determining a linear mean switching energy value (110) of the electronic power circuit based on a modulated control signal with linear modulation; determining a nonlinear mean switching energy value (120) of the electronic power circuit based on a modulated control signal with nonlinear modulation, in particular overmodulation; determining a scaling factor value (130) based on the linear mean switching energy value and the nonlinear mean switching energy value; and determining the power dissipation value (140) based on the linear mean switching energy value and the scaling factor value.Furthermore, a computing unit designed and equipped to execute the procedure (100) is disclosed.