276 results about "Current vector" patented technology

The invention discloses a current transformer real-time state diagnosis system based on Internet of Things, which relates to the technical field of electrical equipment state diagnosis and comprises a reference construction module, a disturbance excitation module, a modeling identification module, a driving unwrapping module, a self-adaptive setting module and a closed-loop control module, in the operation process of a secondary winding loop of the current transformer, a nanosecond time synchronization reference is established, a phase reference baseline is locked, current vector trajectories are continuously collected based on the time synchronization reference and the phase reference baseline, and a discrete phase residual image is constructed. According to the method, through high-precision time synchronization, phase disturbance excitation, sparse modeling identification, driving unwrapping and self-adaptive setting control, hysteresis oscillation of the secondary circuit of the current transformer is accurately identified and suppressed, the fault diagnosis accuracy and the system stability are remarkably improved, and the limitation of a traditional method in the aspects of identification sensitivity and response capability is broken through.

The invention belongs to the field of power system relay protection, and provides a mine cable high-resistance grounding fault line selection method and system for a coal mine power grid, and the method comprises the steps: calculating the zero-sequence current vector of each line before and after a fault based on the zero-sequence current of each line before and after the fault; determining the zero-sequence current variable quantity of each line before and after the fault according to the difference value of the zero-sequence current vector of each line before and after the fault; based on the zero-sequence current variation of each line before and after the fault, performing signal detection by using an oscillator chaotic system to obtain output phase diagrams of different lines; and performing fault line selection according to the states of the output phase diagrams of different lines, and determining a fault line. According to the method, the fault line is judged according to the principle that the phase and the amplitude of the zero-sequence current variable quantity of the fault line are different from the phase of the zero-sequence current variable quantity of the non-fault line, and the zero-sequence current variable quantity of the non-fault line is the same, so that the fault line can still be judged under the condition that the three-phase load is unbalanced; and the accuracy and the universality of high-resistance grounding fault line selection are improved.

The invention relates to the technical field, in particular to a power grid overhead line traveling wave recording fusion fault positioning system, which comprises signal acquisition, traveling wave event stamp capturing, zero-sequence current data flow generation, fault triggering, zero-sequence integral comparison based on time reference to generate an activation instruction, and fault recording. The characteristic topology associates and fuses the traveling wave amplitude and the zero-sequence peak value, calculates a node attenuation rate and marks a breakpoint, and the positioning solution links a double-end timestamp and a wave velocity library according to the position of the breakpoint to output a fault coordinate. According to the invention, accurate locking of the fault moment is realized through synchronous acquisition of multi-source signals; a transient window defined by traveling wave triggering ensures complete capture of features; branch identification precision is improved through current vector fusion; parameters are automatically adjusted through dynamic wave velocity matching to improve positioning accuracy; time synchronization and wave velocity compensation eliminate the influence of line parameters.

The invention discloses a frequency conversion vector control method for a digital energy-saving pump station, which belongs to the technical field of vector control and comprises the following steps: constructing a coupling vector model, simulating the running states of a pump unit under different working conditions through a virtual test signal, and automatically correcting the coupling vector model; operating data of a pump set are collected in real time, an operating situation feature set is constructed, predictive vector control is carried out, an optimal voltage vector sequence is generated, and meanwhile load fluctuation of a pipe network is predicted; demand pre-judgment is carried out on the starting and stopping time and the action amplitude of the anti-backflow device, a bidirectional disturbance suppression mechanism is constructed, current vector parameters are pre-adjusted, and calculus correction is carried out based on deviation judgment; when multiple pumps operate in parallel, the instantaneous operation efficiency point of the pump set is calculated in real time, the efficiency change trend is predicted, a load distribution scheme is generated, the comprehensive energy efficiency is evaluated, energy efficiency self-optimization is carried out, the comprehensive energy efficiency of the system is improved, and control experience reuse is achieved.

The invention relates to the technical field of fault testing, in particular to a dry-type air-core reactor turn-to-turn short circuit monitoring method based on a magnetic field difference method. According to the method, regularization constraint is introduced in an initial baseline stage to construct a reference electromagnetic coupling matrix, a heat accumulation index is recursively analyzed based on three-phase current energy, a thermally-induced magnetic field drift model is fitted in combination with magnetic field residual errors, and combined with combined constraint of the reference electromagnetic coupling matrix and the thermal drift model, a three-phase electromagnetic coupling model is established. The normal thermally induced magnetic field drift component is dynamically stripped in real-time monitoring; and under the constraint of a reference electromagnetic coupling matrix, fitting and optimizing a current vector through weighted least square state estimation, and integrating magnetic field and current two-dimensional deviation to obtain a structure consistency deviation index for fault monitoring. According to the invention, monitoring is carried out in consideration of a linear electromagnetic transfer rule and nonlinear thermal drift compensation, a complex magnetic field environment and a variable load operation condition of the dry-type air-core reactor are adapted, and continuous and reliable monitoring guarantee is provided for long-term stable operation of equipment.

The invention relates to the technical field of power distribution network automation, and discloses an electrical variable monitoring method for ring main unit operation, which comprises the following steps: acquiring three-phase electrical variable data in response to a condition that a load current change rate exceeds a preset micro-motion excitation threshold value; calculating a reference voltage based on the circuit state equation containing the inter-phase mutual inductance coupling term; the method comprises the following steps: constructing a rotating coordinate system taking a current vector as a reference axis, performing vector decomposition on a voltage deviation vector, separating a resistive temperature drift voltage component parallel to the reference axis, and taking a nonlinear impedance voltage component perpendicular to the reference axis as a monitoring parameter to judge a contact state. According to the method, linear resistance drift caused by conductor temperature rise is effectively decoupled, baseline interference is eliminated, weak nonlinear impedance distortion characteristics caused by mechanical contact degradation can be captured, and the recognition sensitivity and accuracy of early latent faults of the ring main unit are improved.

The invention relates to the technical field of on-line monitoring, in particular to an insulation fault on-line monitoring method and system for a medical IT system control cabinet. The method comprises the following steps: selecting a non-integer frequency multiplication detection frequency according to equivalent ground distributed capacitance in a previous monitoring period, and superposing the non-integer frequency multiplication detection frequency with a fundamental frequency to form a composite signal injection system; collecting signals to calculate a voltage instantaneous harmonic distortion rate change gradient, and selecting a time window to split the leakage current according to the change gradient; on the basis of dispersion estimation signal-to-noise ratio weighted fusion current vectors, insulation resistance and distributed capacitance are calculated; constructing a four-dimensional original feature vector composed of the insulation parameter, the phase difference and the intermodulation component energy; constructing a diagonal weighting matrix based on the resistance-capacitance ratio and the gradient to transform a feature vector, and determining the fault attribution through the Mahalanobis distance calculation with the fault template library. According to the scheme, harmonic interference can be avoided, calculation stability can be improved, insulation instantaneous sudden change can be quickly responded, and different fault types can be accurately distinguished to guide maintenance.

The invention discloses a flux weakening method of a permanent magnet synchronous motor finite control set model prediction control system based on an expected fundamental wave voltage closed loop, and belongs to the technical field of permanent magnet synchronous motor speed regulation control. According to the method, the problems of voltage saturation and poor robustness of a finite control set model prediction control system in a weak magnetic region are solved. According to the method, one-step delay compensation is carried out on the stator current, the stator current predicted value predicted through delay compensation is substituted into the voltage vector model under current vector dead beat control, and the compensated voltage vector reference value can be calculated. And an expected fundamental wave voltage vector is calculated based on the compensated voltage vector reference value, and finally the expected fundamental wave voltage vector is used as feedback of closed-loop flux-weakening control, so that maximum voltage control can be realized, and voltage saturation of a flux-weakening area is avoided. The method provided by the invention has better current dynamic performance, faster acceleration time and better robustness. The method can be applied to field weakening control of the permanent magnet synchronous motor.

The invention relates to the technical field of power electronic control and new energy power generation, and discloses an energy storage type photovoltaic off-grid inverter control method and system. The method comprises the following steps: acquiring an analog voltage signal and an analog current signal, and inputting the analog voltage signal and the analog current signal into a preset adaptive filter to obtain a disturbance component sequence; calculating a disturbance current sudden change degree, and if the disturbance current sudden change degree exceeds a preset sudden change threshold, constructing a to-be-counteracted current vector; determining a target phase lead angle according to the to-be-counteracted current vector and a preset transformer phase lag model, and generating a correction time domain compensation signal; generating a comprehensive modulation signal and an inverter switching instruction sequence to drive an inverter; updating a filter coefficient based on the distortion rate and determining a compensation voltage gain; and performing closed-loop correction on the sampling trigger time sequence of the analog current signal according to the system loop transmission delay to obtain a calibration current sequence. The method can effectively overcome the phase lag of the transformer and the transmission delay of hardware, and improve the electric energy quality under the nonlinear load.

The invention discloses a dual three-phase permanent magnet synchronous motor maximum torque current ratio control method and system based on virtual signal injection, and the method comprises the steps: injecting a bipolar square wave signal into a current vector angle, and calculating the d-q axis current after the bipolar square wave signal is injected through the current vector angle of the bipolar square wave signal; the d-q axis current after the bipolar square wave signal is injected is substituted into the corrected torque equation, the positive polarity torque Tup and the negative polarity torque Tdown of the dual three-phase permanent magnet synchronous motor are calculated and are expanded according to the Taylor series, when the difference between the Tup and the Tdown expanded according to the Taylor series is equal to 0, the difference between the Tup and the Tdown passes through a PI controller and then is superposed with an initial current vector angle beta, and the initial current vector angle beta is obtained. And obtaining a current optimal current vector angle, and calculating a d-q axis reference current required by the dual three-phase permanent magnet synchronous motor. According to the invention, accurate control of the maximum torque current ratio is realized.

The invention relates to the field of intelligent medical treatment, in particular to an electrical impedance imaging method and device based on mixed excitation and a program product. Comprising the steps that an initial current vector and an initial boundary voltage vector of mixed excitation are obtained, the mixed excitation comprises L kinds of excitation, and L is a natural number larger than 1; performing weighted fusion on the L excitation initial current vectors to obtain a mixed excitation current vector, and performing weighted fusion on the L excitation initial boundary voltages to obtain a mixed excitation voltage; performing electrical impedance imaging optimization function calculation based on the mixed excitation current vector and the mixed excitation voltage to obtain conductivity change; the optimization function is used for carrying out regularization calculation on regional potential distribution and conductivity variation based on the mixed excitation current vector and the mixed excitation voltage; an electrical impedance distribution image is generated based on the conductivity change. According to the invention, the resolution of EIT imaging is improved, and the method has good clinical value.

The invention relates to the technical field of power grid safety evaluation, in particular to a power system short-circuit parameter prediction method, system and device based on time-space relevance and a storage medium. A multi-dimensional state vector including a node voltage vector, a branch current vector, a short-circuit impedance matrix, spatial position information and a time feature vector is constructed, and a space-time correlation feature vector including a time-dimensional feature, a spatial-dimensional feature, a space-time coupling feature and a state feature is extracted. Wavelet transform, Fourier analysis and graph theory analysis are adopted to identify a parameter change rule and a propagation effect. A multi-level prediction model of a statistical prediction layer, a deep learning layer and a fusion layer is constructed, and comprehensive description of dynamic characteristics of short-circuit parameters is realized through spatio-temporal feature fusion. A staged training strategy is adopted, and comprises the steps of establishing a basic model through offline training, updating parameters in real time through online learning, and quantifying uncertainty through a probability prediction framework. And a prediction correction mechanism and a reliability evaluation system are established, and a complete prediction-evaluation-correction closed loop is formed.

The invention discloses a self-adaptive virtual synchronous generator control method of an energy storage converter, and relates to the technical field of self-adaptive adjustment. The method comprises the following steps: S1, generating an electrical comprehensive state set based on three-phase voltage and three-phase current of a grid-connected point; s2, constructing a bearing trigger function and evaluating to generate a bearing trigger identifier; s3, obtaining a bearing fault diagnosis result based on the constructed diagnosis sample sequence; s4, according to the bearing fault diagnosis result and the diagnosis sample sequence, an adjustment parameter set is obtained, and an adjustment instruction is issued to the virtual synchronous generator; s5, updating the virtual power angle and the frequency reference; extracting a current vector and remodeling an original voltage reference according to an admittance parameter group; adjusting a power droop target and power angle evolution of a virtual synchronous generator of the energy storage converter according to a projection active instruction and a projection reactive instruction obtained through projection operation; the self-adaptive virtual synchronous generator control method realizes self-adaptive virtual synchronous generator control which keeps voltage shaping and virtual power angle continuity under current bearing constraint.

The invention discloses a generator stator winding single-phase earth fault positioning method, system and device and a medium, and the method comprises the steps: enabling three phases of a generator stator winding to be connected in series end to end to form a series loop; low-frequency voltage pulses are injected into the three-phase winding, and a fault phase is determined by comparing symmetry damage characteristics of tail-end current by adopting a tail-end current vector analysis method; injecting a low-frequency voltage pulse into the current phase winding, detecting the current difference between the head end and the tail end of each parallel branch, identifying a branch with abnormal leakage current by combining a leakage current characteristic analysis method, and determining a fault branch; establishing a high-frequency distribution parameter model, and performing high-frequency voltage pulse injection positioning for multiple times to obtain three independent high-frequency pulse positioning results; and performing weighted fusion on the three independent high-frequency pulse positioning results, and performing optimization by using an intelligent optimization algorithm to obtain an optimized single-phase earth fault position. According to the invention, the accuracy and rapidity of fault diagnosis and positioning can be improved.

The embodiment of the invention discloses a distribution transformer electrical parameter complex field on-line synchronous vector monitoring device and method, and the device comprises a high-precision synchronous vector measurement and collection module and a controller, and the high-precision synchronous vector measurement and collection module is connected with the controller. The high-precision synchronous vector measurement and acquisition module is used for being connected with a neutral line at the low-voltage side of the distribution transformer to be measured and a three-phase line at an outlet, and is used for measuring and synchronously acquiring a zero-sequence voltage vector and a neutral line current vector at the low-voltage side of the distribution transformer to be measured. The controller is used for determining the short-circuit complex impedance of the distribution transformer to be measured according to the zero-sequence voltage vector and the neutral current vector, so as to determine the load loss and the short-circuit voltage of the distribution transformer to be measured according to the short-circuit complex impedance, namely, the zero-sequence voltage vector and the neutral current vector are simply and synchronously measured on the low-voltage side of the distribution transformer. Therefore, on-line monitoring of short-circuit complex impedance and electrical parameters can be realized, and problems in the prior art are solved.

The invention provides a qualitative evaluation and error detection method and system for the out-of-tolerance state of a current transformer, and the method comprises the steps: obtaining the current signals of a group of current transformers related to the same node on a line, constructing the physical relation of the current signals, and obtaining a KCL residual data set; standardization processing is carried out, an evaluation standard model is established by adopting RPCA, and a fault current transformer and a time period in which a fault occurs are screened out; current signals of the current transformer in the time period are extracted, a node current vector and an objective function with the minimum absolute value are constructed based on KCL constraint, and an optimization model is established; and obtaining a local optimal solution according to a QPSO optimization algorithm, and continuously iterating to reach a final condition to obtain a global optimal solution, namely solving to obtain a ratio error and a phase error of the group CT. The technical problems that CT metering state evaluation is low in efficiency, high in calculation complexity, large in detection error, low in universality, incomplete in error type identification and prone to causing false alarm or missing detection of the out-of-tolerance current transformer are solved.

The invention relates to an overvoltage risk assessment method, device and equipment for non-full-phase operation of a new energy access weak power grid system. The method comprises the following steps: acquiring electrical quantity data of the new energy access weak power grid system, and a voltage source, grid-connected equivalent impedance, series equivalent impedance and non-full-phase operation line impedance of a power transmission line of the new energy access weak power grid system with a single-phase fault; calculating n positive sequence current vectors and negative sequence current vectors according to each piece of electrical quantity data; calculating n positive sequence port voltage vectors and negative sequence port voltage vectors according to the fault data, each positive sequence current vector and each negative sequence current vector; according to the positive sequence voltage component rated value, each positive sequence port voltage vector and each negative sequence port voltage vector, actual positive sequence voltage and actual negative sequence voltage are obtained through calculation; and according to the actual positive sequence voltage, the actual negative sequence voltage and the positive sequence voltage component rated value, calculating to obtain a single-phase voltage maximum value, and according to the single-phase voltage maximum value, judging whether the system has an overvoltage risk in a non-full-phase operation state.

The invention provides a deep brain stimulation method and system based on controllable current vectors of high-channel-number electrodes, and the method comprises the following steps: implanting two electrodes into a target region, and enabling a nucleus of the target region to be located between the two electrodes; by selecting different contacts on the stimulating electrodes, multiple channels of induced currents in different directions are generated in a plane constructed by the two electrodes; vector current is formed through vector superposition of the induction current of each channel, and the vector current acts on the target nuclei. The high-channel-number electrodes are adopted, programming control is carried out between the two electrodes, accurate control over current vectors is achieved, control over the magnitude and direction of target region nuclei stimulation current is accurately achieved through current vector superposition, therefore, a brain lesion area can be stimulated more accurately, meanwhile, the current vectors can be accurately controlled, and the stimulation effect of the brain lesion area is improved. And unnecessary current is prevented from diffusing to surrounding normal brain tissues, so that side effects caused by stimulation of a non-target area are reduced.

The invention discloses a current source inverter power supply permanent magnet synchronous motor system control method and system, and belongs to the field of permanent magnet synchronous motor control. Establishing a discrete state space equation of the dq-axis current source inverter power supply type permanent magnet synchronous motor system by using state variable information of a control system of the permanent magnet synchronous motor system at a sampling k moment; designing a filter capacitor voltage estimator, obtaining a filter capacitor voltage estimated value, designing a feedback-integral controller, and solving a dq-axis inverter output current control instruction; three optimal current vectors closest to an inverter output current control instruction are selected, the optimal current vectors and the optimal duty ratio are calculated, an optimal switching pulse sequence is output to act on a switching tube of the current source inverter, and current control over the current source inverter power supply permanent magnet synchronous motor system is achieved. The method is high in control precision and high in dynamic response speed.

The invention relates to a permanent magnet synchronous motor MTPA control method based on a double-virtual direct current signal injection mode, in particular to a motor control method, and particularly relates to a control method of a built-in permanent magnet synchronous motor. A pair of virtual direct-current signals with the same amplitude and opposite polarities are injected into a current vector angle beta, Taylor expansion is carried out on electromagnetic torque containing the pair of signals, subtraction is carried out on the two signals to obtain an approximate value of the torque to a first-order partial derivative of the current vector angle, and the approximate value is input into an integral regulator; when the input quantity is controlled to be 0, the optimal current vector angle beta mtpa can be obtained, and MTPA control is achieved. In order to improve the dynamic performance and the steady-state performance of control at the same time, virtual direct-current signals with different amplitudes are selected for injection under different working conditions, the motor can be made to rapidly approach the working state of the optimal current vector angle, and fluctuation of the current vector angle in the stable state is reduced.

The invention discloses a control method and system for an AC / DC access flexible interconnection device. The method comprises the following steps: judging an operation mode of a transformer area; calculating an interconnection voltage difference value and a phase angle difference value; if the voltage difference is smaller than the closed-loop voltage difference threshold value and the phase angle difference threshold value, the flexible interconnection device is switched into an interconnection operation mode; acquiring input and output voltage and current, direct current bus voltage and current and direct current leading-out bus voltage and current of the series-parallel module; converting the three-phase voltage and current measurement value into a voltage and current value under a dq coordinate system; outputting optimized voltage and current values by adopting a PSO (particle swarm optimization) algorithm; calculating a reference voltage current vector and action time, and generating switching signals of each phase; performing error calculation to obtain a voltage and current error signal value; issuing voltage and phase regulation and current regulation instructions, and dynamically regulating voltage and current signals. According to the method, the electric energy quality treatment requirements of the micro-grid in complex dynamic scenes such as high-power pulsating load and distributed power supply power fluctuation can be met.

The invention discloses a cutting machine motor intelligent temperature management method and system based on load prediction, relates to the technical field of cutting machine motor temperature management, and is used for solving the problems of temperature response lag and local overheating under the conditions of complex tracks and load fluctuation. In the operation process of the cutting machine, three-phase stator side current signals of the motor are continuously captured, a current vector input quantity is obtained through coordinate transformation and input into the sliding mode observer to estimate the rotor position and the motor rotating speed, a load trend quantity is generated, combined compensation modulation is carried out, and a compensation value is output to a power output link to dynamically adjust the duty ratio. According to path analysis, marking a hot stacking sensitive path section, calculating a power output change rate and shielding wind flow disturbance intensity, screening out a thermal response to-be-detected section, collecting data through a thermosensitive channel to construct a regional thermal risk index, executing differential air cooling adjustment and power modulation path adjustment, and recording state data in real time; and fine management of the full-working-condition temperature of the motor of the cutting machine is realized.

The invention discloses a direct-current system ground fault real-time monitoring method and system, and relates to the field of intelligent power distribution, and the method comprises the steps: collecting the bus voltage, branch current and disturbance response signals of each branch, constructing a fusion abnormal factor in a fixed monitoring window, comprehensively reflecting the voltage change rate, disturbance amplitude response and current vector offset characteristics, and carrying out the real-time monitoring of the ground fault of a direct-current system. And inputting the factor and a disturbance parameter into a nonlinear scoring function together, and outputting a grounding probability confidence score. And for the branch with the scoring result exceeding a set threshold value, the system executes bypass closing and main branch opening operation, voltage and current derivative data are collected in a recovery window, the voltage drop recovery rate is calculated, and whether an actual grounding point is formed or not is judged. And if the fault is confirmed to be true, the isolation state is maintained, and branch reset operation is completed through a recovery criterion and a manual permission mechanism in a subsequent period. The method has better effects in real-time performance, accuracy and safety.

The invention provides a power distribution network node harmonic exceeding main cause identification method, device and system and a medium, and the method comprises the steps: building a node admittance matrix based on the node harmonic voltage and branch current monitoring data of a power distribution network, building a related equation of the harmonic voltage and an injection current, and employing a compressed sampling matching pursuit algorithm to identify the harmonic exceeding main cause of the power distribution network; solving a sparse harmonic injection current vector, and calculating a node harmonic voltage distortion rate according to a harmonic current injection value so as to judge a standard exceeding condition; through a modal analysis method, harmonic current threshold comparison and multi-frequency superposition effect analysis, identifying main factors exceeding the standard, including harmonic injection standard exceeding, multi-frequency superposition and resonance phenomena; and quantizing contribution degrees of resonance and harmonic injection, and distinguishing composite causes of harmonic exceeding. According to the method, the problem that the harmonic cause is unknown in the harmonic exceeding scene is solved, and the accuracy of the harmonic exceeding cause is remarkably improved. Through simulation and actual measurement verification, the accuracy of the method provided by the invention is verified.

The application relates to a cement rotary kiln control parameter optimization method, which comprises the following steps: firstly, obtaining each target bit number data type related to the cement f-CaO content under the target cement rotary kiln working state; then, obtaining each to-be-referenced optimal control parameter vector based on a vector composed of each target bit number data type data value at each to-be-analyzed time point; then, obtaining the to-be-referenced optimal control parameter vector with the highest similarity to the current vector in each to-be-referenced optimal control parameter vector based on a current vector composed of the data values of each target bit number data type of the target cement rotary kiln under the current working state, and forming a target optimal control parameter vector; finally, adjusting each target bit number data type corresponding to the current working state of the target cement rotary kiln with the target optimal control parameter vector as the target; in this way, the working condition gradually approaches or reaches the historical best level, so that the output and quality of the clinker are effectively improved.

The embodiment of the invention discloses a distribution transformer operation gear synchronization vector online detection method and device, and the method comprises the steps: obtaining a nameplate parameter of a distribution transformer, and carrying out the calculation to obtain a short-circuit impedance value of a low-voltage side to a high-voltage side under each gear; synchronously measuring a voltage vector of the low-voltage side of the distribution transformer, an output current vector and a neutral point voltage vector; when the amplitude of the low-voltage-side zero-sequence current reaches a current detection threshold value or the module value of the low-voltage-side neutral point voltage vector reaches a voltage detection threshold value, obtaining a detection loop and combining a circuit principle and a low-voltage-side synchronous voltage vector, a synchronous current vector output by the low-voltage side and a low-voltage-side neutral point synchronous voltage vector of the distribution transformer; calculating to obtain a short-circuit impedance value of the low-voltage side to the high-voltage side; calculating to obtain the absolute value of the impedance difference value of each gear; determining the gear corresponding to the minimum absolute value of the impedance difference value of each gear as the current operation gear of the distribution transformer; the operation gear of the transformer can be accurately detected on the low-voltage side in the operation state.

The invention discloses a phasor differential protection method and system based on regulation and control characteristics of a low-frequency converter, and belongs to the technical field of relay protection. The method comprises the following steps: calculating negative-sequence current and positive-sequence voltage at two sides of a protected line based on three-phase voltage and current phasors; judging whether the drop depth of the positive sequence voltage meets a three-phase fault criterion, if so, not adjusting a braking coefficient, and if not, adjusting the braking coefficient through the amplitude ratio of the negative sequence current, and calculating a self-adaptive braking coefficient based on the regulation and control characteristics of the low-frequency converter based on the adjusted braking coefficient; and constructing a phasor differential protection criterion based on the adaptive braking coefficient, obtaining fault current vectors at two sides of the protected line, and starting phasor differential protection for the protected line when the fault current vectors meet the differential protection criterion. According to the method, protection sensitivity and reliability can be considered, and the sensitivity of main protection of the flexible low-frequency power transmission line is improved.

The application provides a dual-electricity-controlled multi-phase current sampling crosstalk correction system and method with a boosting function, which comprises a dual-electricity-controlled three-phase circuit, a boosting circuit module and a dual-electricity-controlled single-chip microcomputer. The dual-electricity-controlled three-phase circuit comprises a GM motor three-phase circuit and a TM motor three-phase circuit. The boosting circuit module comprises a first phase boosting unit and a second phase boosting unit. The dual-electricity-controlled single-chip microcomputer collects eight-way phase current signals corresponding to the GM motor three-phase circuit, the TM motor three-phase circuit and the boosting circuit module. A software compensation module is further arranged in the dual-electricity-controlled single-chip microcomputer. A crosstalk compensation matrix is preset in the software compensation module. The software compensation module constructs eight-dimensional phase current signal vectors from the eight-way phase currents, calculates the product of the eight-dimensional phase current vectors and the crosstalk compensation matrix, obtains eight-dimensional calibrated current vectors, extracts each phase real current signal in the eight-dimensional calibrated current signal and outputs the same.

The present invention provides a text adversarial attack method based on Gaussian white noise, belonging to the technical field of natural language processing. First, a natural language text is input into the model. After passing through the word embedding layer, the core layer, and the linear layer, the forward training loss is obtained, and the gradient is obtained through backpropagation. Then, several perturbation terms are added to the gradient of the word embedding vector to generate an adversarial sample, and the forward calculation of the loss value is continued. After multiple iterative trainings, the model can learn the optimal solution within a very small range of changes in the current vector. The perturbation terms prompt the update of the model parameters to move in the direction of increasing loss, achieving the purpose of attacking the model. In this process, the present invention makes the intensity of parameter update have a certain randomness within a set range by adding Gaussian white noise perturbation terms, so that the model has higher fault tolerance performance and improves the accuracy of the model.

The invention relates to the technical field of motor speed regulation, in particular to a method and system for regulating the speed of a motor by adjusting flux weakening, and the method comprises the following steps: detecting the operation state of the motor, and obtaining the operation state data; calculating a voltage limit ellipse and a current limit circle according to the operation state data; calculating a current vector trajectory which simultaneously meets the constraints of the voltage limit ellipse and the current limit circle; calculating a motor target rotating speed according to the motor operation state data and the motor parameters; and by adjusting the direct-axis current component and the quadrature-axis current component of the motor stator and combining the target rotating speed, controlling the stator current vector to move according to the calculated current vector trajectory, thereby realizing flux-weakening speed expansion. A voltage limit ellipse, a current limit circle and a flux weakening control current vector track are calculated, so that direct-axis and quadrature-axis current components of the stator can be accurately adjusted under different working conditions, the rotating speed of the motor is controlled within a target range, and the problem that the speed adjusting precision is not high enough is effectively solved.