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37results about How to "Eliminates DC bias" patented technology
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Stator flux linkage estimation method of permanent magnet synchronous motor based on direct torque control
ActiveCN103731082AEliminates DC biasEliminate errorsElectronic commutation motor controlAC motor controlPhysicsTarget control
The invention discloses a closed loop flux linkage estimation method which is applied to a direct torque control system of a permanent magnet synchronous motor. Calculation is conducted through voltage signals and current signals measured in a real-time sampling mode according to a voltage method flux linkage calculation formula so that initial estimation flux linkage can be obtained, then, the initial estimation flux linkage and target control flux linkage are used as input quantity, a PI regulator is used for conducting dynamic state closed loop correction, and accordingly the target control flux linkage can be tracked ultimately. The given control flux linage controlled by direct torque is used as the amplitude of the target control flux linkage in a flux linkage estimator, the rotor position angle is obtained through a position sensor, and the angle information is dynamically compensated to be used as the angle information of the target control flux linkage. Through closed loop regulation to the voltage method flux linkage estimator, flux linkage calculation deviation caused by direct current bias and initial integration in an integration element can be effectively eliminated, the real flux linkage can be accurately estimated, and good rapidity and robustness are achieved in the actual direct torque control system.
Owner:SOUTHEAST UNIV
Method for predicting direct power of improved T type three-level permanent magnetic direct drive wind power system
InactiveCN106877408AGuaranteed maximum utilizationReduce distortion rateSingle network parallel feeding arrangementsWind energy generationPower factorEngineering
The invention discloses a method for predicting direct power of an improved T type three-level permanent magnetic direct drive wind power system. A topological structure of the permanent magnetic direct drive wind power system is an improved T type three-level converter. According to an SVPWM technology, the problem that a switching frequency is not fixed, the system loss is reduced and a power factor of the system is improved. A machine side converter control strategy is a prediction direct power control strategy. A rotating speed loop is an external loop. A power loop is an internal loop. The power loop is prediction power control. A PI adjustor is not required. A control structure is simple and an effect is good. A network side direct power control strategy is a direct power control strategy based on virtual flux orientation. A power network voltage does not need to be sampled. A structure is simple. The system cost is reduced. The dynamic stability is improved. The prediction direct power control strategy and the direct power control strategy based on virtual flux orientation are based on space vector pulse width modulation (SVPWM), so the system has a fixed switching frequency and unit power factor.
Owner:YANSHAN UNIV
Intermediate-frequency and radio-frequency universal target simulator for pulse pressure radar
ActiveCN102419434AAvoid amplitude balanceAvoid phase balanceWave based measurement systemsFrequency spectrumIntermediate frequency
The invention discloses an intermediate-frequency and radio-frequency universal target simulator for a pulse pressure radar. The target simulator comprises a power supply module, a reference source generating module, a control display module, an intermediate frequency analog signal generating module, an amplitude regulating module and a hybrid frequency filtering module; the amplitude regulating module is divided into amplitude regulating modules A and B; the hybrid frequency filtering module is divided into hybrid frequency filtering modules A and B; the power supply module is connected withother modules; the reference source generating module is respectively connected with the control display module and the intermediate frequency analog signal generating module; the control display module is respectively connected with the intermediate frequency analog signal generating module, the amplitude regulating module A and the amplitude regulating module B; the intermediate frequency analog signal generating module is respectively connected with the amplitude regulating module A and the amplitude regulating module B; the amplitude regulating module A is connected with the hybrid frequency filtering module A; and the amplitude regulating module B is connected with the hybrid frequency filtering module B. The target simulator provided by the invention has the advantages of simplifiedcircuit, pure frequency spectrum, integrity of the intermediate frequency and the radio frequency, abundant functions, real data and strong pertinence.
Owner:TIANWEI ELECTRONICS SYST ENG
Neutral point potential balance control method for direct current side in NPC three-level structure
ActiveCN103414366AEliminates DC biasEliminate low frequency fluctuationsAc-dc conversionPhotovoltaic energy generationDC biasBus voltage
The invention relates to a neutral point potential balance control method for a direct current side in an NPC three-level structure. A neutral point clamping type three-level inverter circuit is adopted in a photovoltaic grid-connected inverter, so that neutral point potential imbalance is prone to being caused; a software control algorithm, namely, a control method conducting hysteresis comparison on a neutral point cannot not completely eliminate low frequency fluctuation of neutral point potential; a control algorithm for injecting zero sequence voltage is relatively complex. The neutral point potential balance control method for the direct current side in the NPC three-level structure is characterized in that the difference value of one half of busbar voltage on the direct current side of a photovoltaic inverter and neutral-point voltage, the current value which needs to be injected into the neutral point in a present switching period is obtained by a PI regulator, the acting time of redundant small vectors in each sector in space vector pulse width modulation is used as a modulation method, and the allocation proportion of the redundant small vectors in one switching period is computed. The neutral point potential balance control method for the direct current side in the NPC three-level structure eliminates direct current bias and low frequency fluctuation of the neutral-point potential of a diode clamping type three-level inverter on the existing hardware condition, and neutral-point balance is achieved.
Owner:XIAN LONTEN RENEWABLE ENERGY TECH
A parameter training algorithm for EEG signals in a multi-classifier single-channel mode
PendingCN109165615ASolve the problem of collection accuracySolve the speed problemCharacter and pattern recognitionCode moduleSupport vector machine
The invention discloses a parameter training algorithm for EEG signals in a multi-classifier single-channel mode, belonging to the technical field of EEG signal processing. The algorithm includes a system initialization parameter setting module, a multi-classifier training module, a compression coding module, and an indexing and the best classifier finding module. The multi-classifier training module includes a convolutional neural network, a support vector machine, a K nearest neighbor, and a feedforward neural network. The input original signal is compressed into index data according to Huffman coding mode, and the Huffman compression algorithm re-encodes the original data by extracting a common identifier. The classification accuracy of the classifier is tested according to the index data synthesized from the original data. The invention can flexibly select the optimal classification model according to different EEG signal characteristics, and the compression index algorithm makes full use of the cache for information storage, reduces hardware overhead, reduces algorithm complexity, and is convenient for subsequent algorithm expansion.
Owner:ACADEMY OF MILITARY MEDICAL SCI
Control method of bidirectional full-bridge DC/DC converter circuit and suppression magnetic biasing
InactiveCN109450255AEliminates DC biasBias suppressionDc-dc conversionElectric variable regulationDc converterEngineering
The invention belongs to the field of the bidirectional full-bridge DC / DC converter circuit control, and especially relates to a control method of bidirectional full-bridge DC / DC converter circuit magnetic biasing. The control method comprises the following steps: performing closed-loop regulation on an AC side current average value of a circuit, and adjusting the duty cycle of a circuit secondaryside according to closed-loop regulation. Through the control method disclosed by the invention, the secondary side AC side voltage is adjusted within short time through the closed-loop control on the AC side current, so that the AC side current can quickly recover to the steady-state current, the DC bias of the recovery process is reduced and then eliminated, the control method has important significance for the application of the bidirectional full-bridge DC / DC converter circuit in a power change occasion.
Owner:HEFEI KEWELL POWER SYST CO LTD
Method for eliminating dc bias for receiver and signal process module
InactiveCN1917380ASimple structureImprove computing efficiencyTransmissionMulti-frequency-changing modulation transferenceIdle timeComputer science
The invention is used to solve the problem of which the DC bias can not be simply and accurately removed from the signal processor in the receiver. It comprises the following steps: the control module supervises the state of each time slot in the logic channel, informs the idle time slot to the calculation module and disconnects the receiving signal of the signal processor in the idle time slot; according to the sampling signal outputted from the signal processor in the idle time slot, the calculation module calculates the DC bias value of the signal processor and outputs the result to the bias removing module; according to said DC bias value, the bias removing module removes the DC bias of the sampling signals from the signal processor.
Owner:GLOBAL INNOVATION AGGREGATORS LLC
Method and device for eliminating direct current offset
InactiveCN102035771AEliminates DC biasThe elimination effect is accurate and reliableDc level restoring means or bias distort correctionPhase-modulated carrier systemsMinimum weightSymbol of a differential operator
The invention provides a method and a device for eliminating direct current offset. The method comprises the following steps of: calculating the Euclidean distance between every two of a plurality of quadrature phase shift keying (QPSK) modulation-based demodulation symbols; determining four sets from the plurality of demodulation symbols, wherein every set corresponds to a modulation direction of QPSK modulation; performing Euclidean distance weighted summation calculation on the four determined sets respectively and selecting a demodulation symbol which has a minimum weighted summation value and serves as a rough estimation point of QPSK modulation in every set; re-determining four sets from the plurality of demodulation symbols according to the Euclidean distance between each modulation symbol and the rough estimation point; performing Euclidean distance weighted summation calculation on the four re-determined sets respectively and selecting a demodulation symbol which has a minimum weighted summation value and serves as a precise estimation point of QPSK modulation in every set; and performing direct current offset calculation and compensation according to the precise estimation point. The demodulation performance of a system can be enhanced.
Owner:ST ERICSSON SEMICON BEIJING
Method and device for suppressing DC bias of DAB converter, and storage medium
ActiveCN110995000AEliminates DC biasDc-dc conversionElectric variable regulationSquare waveformPhase shifted
The invention discloses a method and a device for suppressing DC bias of a DAB converter, and a storage medium, and relates to the field of bidirectional active bridge DC-DC converter control. The method comprises the steps: obtaining a first external phase shift angle between two full bridges of a previous steady state in a DAB transient process, wherein the two full bridges respectively output afirst square wave and a second square wave, and a phase difference value between the first square wave and the second square wave is the first outer phase shift angle; when entering a DAB transient process, respectively changing the pulse widths of the first square wave and the second square wave; and obtaining a phase shift angle according to the first square wave and the second square wave after the pulse width is changed. According to the technical scheme provided by the invention, the main purpose is to directly change the power transmission direction and / or size by changing the pulse widths of the two square waves in the transient process after the previous steady state, thereby eliminating the direct current bias generated in the transient process under the traditional single phaseshift.
Owner:SHENZHEN UNIV
DC magnetic biasing suppression method for bidirectional full-bridge DC/DC converter
ActiveCN109391155AEliminates DC biasBias suppressionDc-dc conversionElectric variable regulationPhase shiftedDc converter
The invention discloses a DC magnetic biasing suppression method for a bidirectional full-bridge DC / DC converter, and belongs to the field of bidirectional full-bridge DC / DC converter circuit control.The suppression method comprises: calculating a required phase shift angle after power change, in a first cycle after the required power change, quantitatively changing the phase shift angle and dutycycle of a secondary side, and working at a steady phase shift angle in a second cycle after the required power change. The suppression method of the invention can quickly restore the current flowingthrough a transformer to the steady current after the power change by controlling the voltage at a secondary side AC side in one cycle, to eliminate the DC bias of the restoring process, thereby suppressing the magnetic biasing, and is of great significance for the bidirectional full-bridge DC / DC converter circuit in applications where power is changed.
Owner:STATE GRID JIANGSU ELECTRIC POWER CO LIANYUNGANG POWER SUPPLY CO +3
Impedance identification method of power grid of grid-connected inverter based on high-frequency signal injection
ActiveCN110045187AEnsure effective injectionImproving the accuracy of impedance identificationResistance/reactance/impedenceGrid-tie inverterIntegral controller
The invention provides an impedance identification method of a power grid of a grid-connected inverter based on high-frequency signal injection. The method comprises the following steps: firstly, respectively measuring the voltage and bridge arm side current of the grid-connected inverter by using a voltage sensor and a current sensor, and converting the voltage and the bridge arm side current through a proportional integral controller to obtain a modulated voltage signal; then, injecting a three-phase high-frequency voltage signal into the modulated voltage signal to update the voltage of thegrid-connected inverter, measuring the power grid side current of the grid-connected inverter by using the current sensor, and respectively substituting the updated voltage and the power grid side current into a voltage extraction module and a current extraction module; and finally, extracting a high-frequency voltage signal and a high-frequency current signal of a grid of the grid-connected inverter by using an improved complex number filter so as to solve an impedance value of the power grid in real time. According to the impedance identification method provided by the invention, the three-phase high-frequency voltage signal is directly superimposed on the modulated voltage signal, thereby ensuring the effective injection of the high-frequency signal and being able to improve the signal-to-noise ratio of the power grid, so that the impedance identification accuracy of the power grid is improved.
Owner:ZHENGZHOU UNIVERSITY OF LIGHT INDUSTRY +1
Photodiode circuit based on background noise elimination and laser ranging system
ActiveCN104359455AEliminates DC biasImprove signal-to-noise ratioWave based measurement systemsOptical rangefindersCapacitanceIntegrator
The invention discloses a photodiode circuit based on background noise elimination and a laser ranging system. The photodiode circuit based on background noise elimination, provided by the invention, comprises a photodiode transconductance amplifier module, an operational amplification integrator module and a filtration module, wherein the filtration module is connected to the output end of the photodiode transconductance amplifier module and the input end of the operational amplification integrator module; and the output end of the operational amplification integrator module is connected to the input end of the photodiode transconductance amplifier module. According to the photodiode circuit disclosed by the invention, only an operational amplifier, a capacitor and a resistor can be used by the operational amplification integrator module, only a capacitor and a resistor can be used for a filter circuit, a digital element is not used in the whole circuit, extra noise is avoided, the signal to noise ratio of the circuit can be greatly improved, and the ranging range is widened. Meanwhile, because only the operational amplifier, the resistor and the capacitor are used, the cost is greatly reduced compared with the prior art, and the overall circuit area is greatly reduced, so that miniaturization of the product is facilitated.
Owner:SHENZHEN KYLE OPTICS TECH CO LTD
Transformer direct current bias suppression method for alternating current-direct current-alternating current power supply system of locomotive
ActiveCN108879630AAchieve compensationAchieve inhibitionEmergency protective arrangements for limiting excess voltage/currentTransformerPower grid
The invention relates to an alternating current-direct current-alternating current power supply system with transformer power supply for a locomotive or a motor car, in particular to a transformer direct current bias suppression method for the alternating current-direct current-alternating current power supply system of the locomotive. The problems existing in an existing alternating current-direct current-alternating current power supply system of the locomotive in overcoming the transformer direct current bias are solved. When transformer direct current bias suppression method for the alternating current-direct current-alternating current power supply system of the locomotive works through four quadrants, positive accumulation processing and negative accumulation processing of a plurality of power grid cycles are carried out on the input voltage of the four quadrants in the positive and negative half cycle of the power grid voltage. According to the actual working conditions, after the positive and negative half cycle phase intervals of the fundamental wave of the input voltage are accurately calculated, positive accumulation processing and negative accumulation processing of thepower grid cycles are carried out on the input voltage of the four quadrants. Whether direct current bias occurs or not is judged through four quadrant input voltage and current, when the direct current bias occurs, PI regulation is carried out on the accumulated value of the positive and negative half cycle of the current to change the output result of a current loop so as to adjust the PWM pulse width and realize the compensation and suppression of the direct current bias.
Owner:CRRC YONGJI ELECTRIC CO LTD
Neural signal amplifier based on MTJ device
PendingCN111711426AReduce occupancyEffectively identify and amplifyAmplifier modifications to reduce non-linear distortionPush-pull amplifiersCapacitanceResistance capacitance
The invention discloses a neural signal amplifier based on an MTJ device, and belongs to the technical field of biological signal processing. An amplifier is provided with two amplifier feedback loops, a pseudo resistor RH is composed of an MTJ and an MOS tube, selective amplification is conducted on signals in the frequency band lower than 300 Hz according to the amplitude of the signals, and inother words, only high-pulse neural action signals are effectively recognized and amplified. The pseudo resistor RH is formed by connecting the MTJ and the MOS tube in series, so the problem that thepositive and negative directions of MOS current are not matched is solved, the noise is lower, the distortion of the amplifier is reduced, and the interference to a neural signal is also reduced. Dueto the fact that the pseudo resistor has extremely high resistance, the capacitor C2 can achieve a very low low-frequency cut-off point without a very large area, the chip area is reduced to a certainextent; in addition, the MTJ is directly manufactured in the fourth layer of metal and the fifth layer of metal through the MEMS technology, and the occupation of the chip area is also reduced.
Owner:南京明尼晶磁电子科技有限公司
Compensation method for non-linear periodic oscillation of PMSM position signal
InactiveCN107579692AReduce the impactReduce lossElectronic commutation motor controlVector control systemsPermanent magnet synchronous motorAngular velocity
The invention discloses a compensation method for non-linear periodic oscillation of a permanent magnet synchronous motor (PMSM) position signal. The compensation method includes the steps of acquiring the actual angular velocity and the actual angle of a rotor of the PMSM, obtaining an ideal angular velocity according to the actual angular velocity, obtaining the angular velocity difference through the ideal angular velocity and the actual angular velocity, obtaining the angle deviation according to the angular velocity difference, and using the angle deviation to compensate the actual angleof the rotor. According to the compensation method, compensation for the non-linear periodic oscillation of position signals is realized. The compensation method is simple, the operation is convenient, and the influence of the signal nonlinear periodic oscillation on the operation of the motor can be reduced to a certain extent. The actual engineering data shows that DC bias in the three-phase current can be effectively eliminated, the motor loss is reduced, and the operation stability of the motor is guaranteed.
Owner:CSR ZHUZHOU ELECTRIC LOCOMOTIVE RES INST
Voltage model stator flux linkage estimation method
ActiveCN108075704AEliminates DC biasImprove observation dynamic response speedElectronic commutation motor controlElectric motor controlEstimation methodsElectromotive force
The invention discloses a novel improved voltage model stator flux linkage estimation method. The method comprises the steps: obtaining stator counter induced electromotive forces ys(alpha) and ys(beta) comprising DC components through a DC bias elimination module according to the collected and calculated asynchronous motor stator counter induced electromotive forces and stator angular frequency in a stationary coordinate system; finally obtaining an estimated alpha-axis stator flux linkage (shown in the description) and an estimated beta-axis stator flux linkage (shown in the description) through a flux linkage calculation module. Compared with a conventional technical scheme, the method is advantageous in that 1, the method solves a problem of DC bias and steady-state error of a voltagemodel flux linkage observer; 2, the method is higher in dynamic response speed of flux linkage estimation.
Owner:HEFEI UNIV OF TECH
Calculation method and system of flux linkage
InactiveCN105811841AEliminates DC biasAchieve compensationElectronic commutation motor controlVector control systemsNonlinear distortionLow distortion
The invention discloses a calculation method and system of a flux linkage, applied to a stator or a rotor. The calculation method of the flux linkage comprises feed-forward integral treatment, coordinate conversion, amplitude limiting treatment and low-pass filtering treatment for an input voltage; the feed-forward integral treatment and the low-pass filtering treatment compose a double-integral link which can remove problems of nonlinear distortion and saturated drifting, realize complete compensation of an amplitude value and a phase, and enable the finally output waveform to have a good sine degree and very low distortion. In addition, adjustment of the amplitude value can be realized through the amplitude limiting processing, so that the amplitude is not greater than a preset stator or rotor flux linkage amplitude value. Therefore, the direct current offset of the output waveform can be removed efficiently.
Owner:CSR ZHUZHOU ELECTRIC LOCOMOTIVE RES INST
System with dual coil assemblies for online monitoring chippings in lubricating oil
PendingCN111594295AImprove reliabilityRealize human-computer interactionLubrication indication devicesDual coilControl engineering
The invention discloses a system with dual coil assemblies for online monitoring chippings in lubricating oil. The system comprises a power module, a sensor module, a signal demodulation module and anupper computer, and is characterized in that the power module is provided with a first positive voltage output end, a negative voltage output end, a second positive voltage output end and a third positive voltage output end, the sensor module comprises a sensor driving module used for producing sensor excitation signals, a first excitation module, a first sensing module, a second excitation module and a second sensing module, and the signal demodulation module comprises a first differential amplification module, a first phase-sensitive demodulation module, a first lowpass filtering module, afirst super servo amplifier module, a second differential amplification module, a second phase-sensitive demodulation module, a second lowpass filtering module, a second super servo amplifier module,an AD sampling module and a DSP control module. The system has the advantages that the signal demodulation module has totally two paths, the detection missing rate is effectively lowered, the reliability of the detection result is improved, and the detection efficiency and detection precision are high.
Owner:ZHEJIANG ZHONGXIN POWER MEASUREMENT & CONTROL TECH
Photodiode circuit and laser ranging system based on background noise cancellation
ActiveCN104359455BEliminates DC biasImprove signal-to-noise ratioWave based measurement systemsOptical rangefindersCapacitanceIntegrator
The invention discloses a photodiode circuit based on background noise elimination and a laser ranging system. The photodiode circuit based on background noise elimination, provided by the invention, comprises a photodiode transconductance amplifier module, an operational amplification integrator module and a filtration module, wherein the filtration module is connected to the output end of the photodiode transconductance amplifier module and the input end of the operational amplification integrator module; and the output end of the operational amplification integrator module is connected to the input end of the photodiode transconductance amplifier module. According to the photodiode circuit disclosed by the invention, only an operational amplifier, a capacitor and a resistor can be used by the operational amplification integrator module, only a capacitor and a resistor can be used for a filter circuit, a digital element is not used in the whole circuit, extra noise is avoided, the signal to noise ratio of the circuit can be greatly improved, and the ranging range is widened. Meanwhile, because only the operational amplifier, the resistor and the capacitor are used, the cost is greatly reduced compared with the prior art, and the overall circuit area is greatly reduced, so that miniaturization of the product is facilitated.
Owner:SHENZHEN KYLE OPTICS TECH CO LTD
Rapid power commutation control method for dual-active full-bridge DC/DC converter
PendingCN114825950AEliminates DC biasImplement soft switchingDc-dc conversionElectric variable regulationElectrical resistance and conductanceSquare waveform
The invention provides a rapid power commutation control method for a dual-active full-bridge DC / DC converter, and the method comprises the steps: S1, defining that power is transmitted from a primary side to a secondary side of the dual-active full-bridge DC / DC converter as positive transmission, and otherwise, the power is transmitted as negative transmission; s2, according to an initial power value and a target power value set by a user, judging how to change the direction of the transmission power, and according to known parameters, respectively calculating the required phase shift difference duty ratio sum between the primary side square wave voltage and the secondary side square wave voltage of the high-frequency transformer; and S3, calculating the negative pulse width duty ratio of the adjusted primary side square wave voltage of the high-frequency transformer and the positive pulse width duty ratio of the adjusted secondary side square wave voltage of the high-frequency transformer in the transient process so as to finish conversion from an initial power value to a target power value, eliminate direct current bias and realize soft switching. The equivalent resistance is considered during modeling and analysis, so that the risk that components are damaged can be further reduced, and the stability of the converter is improved.
Owner:SHENZHEN UNIV
Constant On-time Controller for SMPS with Inductor Current Slope Compensation
InactiveCN103840666BEliminates DC biasDc-dc conversionElectric variable regulationVoltage referenceEngineering
The invention relates to a fixed on-time controller for a switch power supply and with an inductance and current slope compensation function. The switch power supply comprises an MOSFE switching tube and a filter inductor, the fixed on-time controller comprises an RS trigger, a time delayer and a comparator, the time delayer is connected with the RS trigger, the output end of the RS trigger is connected with the MOSFE switching tube, the input end of the RS trigger is connected with the output end of the comparator, one input end of the comparator is connected with the output end of the switch power supply, the other input end of the comparator is connected with a direct-current bias correction circuit, the direct-current bias correction circuit comprises a subtracter, an inductance and current feedback bypass and reference voltage, one end of the substrater is connected with the comparator, and the other end of the substrater is connected with the inductance and current feedback bypass and the reference voltage. Compared with the prior art, the fixed on-time controller has the advantages of precisely controlling output voltage and the like.
Owner:SHANGHAI UNIVERSITY OF ELECTRIC POWER
A DC Bias Suppression Method for Bidirectional Full Bridge DC/DC Converter
ActiveCN109391155BBias suppressionEliminates DC biasDc-dc conversionElectric variable regulationTransformerFull bridge
The invention discloses a DC bias suppression method for a bidirectional full-bridge DC / DC converter, which belongs to the field of circuit control of a bidirectional full-bridge DC / DC converter. The suppression method includes: calculating the required phase shift angle after power change , in the first cycle after the required power change, quantitatively change the phase shift angle and duty cycle of the secondary side, and start to work with a steady-state phase shift angle in the second cycle after the required power change . The invention controls the voltage of the AC side of the secondary side in one cycle so that the current flowing through the transformer can quickly recover to the steady current after the power change, and eliminates the DC bias in the recovery process, thereby suppressing the bias magnetism. The application of bridge DC / DC converter circuit in the occasion of power change is of great significance.
Owner:STATE GRID JIANGSU ELECTRIC POWER CO LIANYUNGANG POWER SUPPLY CO +3
Novel universal four-phase-shift modulation method for improving dynamic performance of dual-active bridge
ActiveCN112615549AFast dynamic responseEliminates DC biasEfficient power electronics conversionDc-dc conversionSoft switchingComputation complexity
The invention provides a novel universal four-phase-shift modulation method for improving the dynamic performance of a dual-active bridge. All carrier signals are kept synchronous, and the universal four-phase-shift modulation method adjusts a corresponding phase shift angle by changing parameters of a comparison register in each carrier. The control method provided by the invention is based on a traditional phase shift control method, only input and output voltages need to be measured, and an auxiliary circuit does not need to be added. Compared with other control methods, the method provided by the invention has the advantages that dynamic response is completed instantly, a transition process and inductive current detection are not needed, and the whole control process is irrelevant to an inductance value. The method provided by the invention reduces the cost and calculation complexity, achieves the quick dynamic response of the circuit, eliminates the DC bias of the inductive current in a response process, and can be suitable for all application scenes of hard switching, soft switching, unidirectional power transmission, bidirectional power transmission and the like. Meanwhile, the method is also suitable for all control methods such as single-phase-shift modulation and three-phase-shift modulation.
Owner:SHANGHAI TECH UNIV
Intermediate-frequency and radio-frequency universal target simulator for pulse pressure radar
ActiveCN102419434BAvoid amplitude balanceAvoid phase balanceWave based measurement systemsFrequency spectrumRadar
The invention discloses an intermediate-frequency and radio-frequency universal target simulator for a pulse pressure radar. The target simulator comprises a power supply module, a reference source generating module, a control display module, an intermediate frequency analog signal generating module, an amplitude regulating module and a hybrid frequency filtering module; the amplitude regulating module is divided into amplitude regulating modules A and B; the hybrid frequency filtering module is divided into hybrid frequency filtering modules A and B; the power supply module is connected withother modules; the reference source generating module is respectively connected with the control display module and the intermediate frequency analog signal generating module; the control display module is respectively connected with the intermediate frequency analog signal generating module, the amplitude regulating module A and the amplitude regulating module B; the intermediate frequency analog signal generating module is respectively connected with the amplitude regulating module A and the amplitude regulating module B; the amplitude regulating module A is connected with the hybrid frequency filtering module A; and the amplitude regulating module B is connected with the hybrid frequency filtering module B. The target simulator provided by the invention has the advantages of simplifiedcircuit, pure frequency spectrum, integrity of the intermediate frequency and the radio frequency, abundant functions, real data and strong pertinence.
Owner:TIANWEI ELECTRONICS SYST ENG
Impedance Identification Method of Grid-connected Inverter Based on High-frequency Signal Injection
ActiveCN110045187BEnsure effective injectionImproving the accuracy of impedance identificationResistance/reactance/impedenceGrid connected inverterGrid impedance
Owner:ZHENGZHOU UNIVERSITY OF LIGHT INDUSTRY +1
Method, device and storage medium for suppressing DC bias of dab converter
ActiveCN110995000BEliminates DC biasDc-dc conversionElectric variable regulationSquare waveformPhase shifted
The invention discloses a method, a device and a storage medium for suppressing a DC bias of a DAB converter, and relates to the control field of a bidirectional active bridge DC-DC converter. The method for suppressing a DC bias of a DAB converter includes: obtaining a DAB The first external phase angle between the two full bridges in the previous stable state of the transient process; wherein, the two full bridges output the first square wave and the second square wave respectively, and the first square wave and the second square wave The phase difference value between the square waves is the first external shift phase angle; when entering the DAB transient process, change the pulse width of the first square wave and the second square wave respectively; according to the first square wave after changing the pulse width Square wave and second square wave, get the phase shift angle. The main purpose of the technical solution proposed by the present invention is to directly change the direction and / or magnitude of power transmission by changing the pulse width of the two square waves during the transient process after the previous steady state, thereby eliminating the traditional DC bias generated by transient process under single phase shift.
Owner:SHENZHEN UNIV
A novel general-purpose four-phase-shift modulation method for improving the dynamic performance of dual active bridges
ActiveCN112615549BFast dynamic responseEliminates DC biasEfficient power electronics conversionDc-dc conversionComputation complexityCarrier signal
The present invention provides a novel general-purpose four-phase-shift modulation method for improving the dynamic performance of dual active bridges. All carrier signals remain synchronized. The general-purpose four-phase-shift modulation method adjusts the corresponding parameters by changing the parameters of the comparison registers in each carrier. phase shift angle. The control method proposed by the present invention is based on the traditional phase-shift control method, and only needs to measure the input and output voltages without adding auxiliary circuits. Compared with other control methods, the method proposed by the present invention completes the dynamic response instantaneously, does not need a transition process, and does not need to detect the inductance current, and the whole control process has nothing to do with the inductance value. The method proposed in the present invention reduces the cost and computational complexity, realizes fast dynamic response of the circuit and eliminates the DC bias of the inductor current during the response process, and at the same time, the method proposed in the present invention can be applied to hard switching, soft switching, unidirectional power transmission, All application scenarios such as two-way power transmission are also applicable to all control methods such as single phase-shift modulation and triple phase-shift modulation.
Owner:SHANGHAI TECH UNIV
Transformer DC Bias Suppression Method for Locomotive AC-DC-DC Power Supply System
ActiveCN108879630BAchieve compensationAchieve inhibitionEmergency protective arrangements for limiting excess voltage/currentFour quadrantsTransformer
The invention relates to an alternating current-direct current-alternating current power supply system with transformer power supply for a locomotive or a motor car, in particular to a transformer direct current bias suppression method for the alternating current-direct current-alternating current power supply system of the locomotive. The problems existing in an existing alternating current-direct current-alternating current power supply system of the locomotive in overcoming the transformer direct current bias are solved. When transformer direct current bias suppression method for the alternating current-direct current-alternating current power supply system of the locomotive works through four quadrants, positive accumulation processing and negative accumulation processing of a plurality of power grid cycles are carried out on the input voltage of the four quadrants in the positive and negative half cycle of the power grid voltage. According to the actual working conditions, after the positive and negative half cycle phase intervals of the fundamental wave of the input voltage are accurately calculated, positive accumulation processing and negative accumulation processing of thepower grid cycles are carried out on the input voltage of the four quadrants. Whether direct current bias occurs or not is judged through four quadrant input voltage and current, when the direct current bias occurs, PI regulation is carried out on the accumulated value of the positive and negative half cycle of the current to change the output result of a current loop so as to adjust the PWM pulse width and realize the compensation and suppression of the direct current bias.
Owner:CRRC YONGJI ELECTRIC CO LTD
A Constant On-time Controller for Switching Power Supply with External Compensation
InactiveCN103887970BEliminates DC biasEffective correctionDc-dc conversionElectric variable regulationMOSFETVoltage reference
The invention relates to a switching power source fixed on-time controller with external compensation. A switching power source comprises an MOSFET switching tube. The fixed on-time controller comprises an RS trigger, a time delayer and a comparator. The time delayer is connected with the RS trigger, the output end of the RS trigger is connected with the MOSFET switching tube, the input end of the RS trigger is connected with the output end of the comparator, one input end of the comparator is connected with the output end of the switching power source, and the other input end of the comparator is connected with a direct current bias correcting circuit. The direct current bias correcting circuit comprises a subtracter, a digital processor and a reference voltage. One end of the subtracter is connected with the comparator, and the other end of the subtracter is connected with the digital processor and the reference voltage. The digital processor and the reference voltage are respectively grounded, and the digital processor outputs the voltage compensation amount to the subtracter. Compared with the prior art, the witching power source fixed on-time controller has the advantages of effectively eliminating direct current bias and being simple in structure.
Owner:SHANGHAI UNIVERSITY OF ELECTRIC POWER
Locomotive traction power supply system, four-quadrant converter control method and system
ActiveCN103684034BEliminates DC biasEliminate Steady State ErrorEfficient power electronics conversionPower conversion systemsControl signalAverage current
The invention discloses a locomotive traction power supply system as well as a control method and system of a four-quadrant current transformer. The control method comprises the following steps: obtaining a first sampling current and a sampling voltage at the input end of the four-quadrant current transformer; obtaining a direct-current bias voltage corresponding to an average current value of the first sampling current; overlapping the negative value of the direct-current bias voltage to the sampling voltage so as to obtain a first modulation voltage; controlling the control end of the four-quadrant current transformer according to a first modulation control signal generated by the first modulation voltage. According to the control method, the direct-current bias in a circuit of the four-quadrant current transformer can be removed, the direct-current magnetic bias phenomenon of a traction voltage transformer is avoided, and stable running of the traction voltage transformer and a locomotive traction power supply network is favorably protected.
Owner:CHINA CNR CORPORATION
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