212 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 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 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 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 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 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 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 application relates to the technical field of general control or regulation systems, and discloses an automatic regulation method for a plug taking pump operation, which comprises the following steps: synchronously acquiring a voltage vector and a current vector of a controlled execution unit; calculating a transient active power by calculating a scalar product of the voltage vector and the current vector; removing a steady power consumption component in the transient active power to extract an energy recoil pulse; generating a micro-elastic recoil energy product representing load yield information by integration; monitoring a differential gradient of the micro-elastic recoil energy product; and determining an output negative gradient duty cycle signal at a collapse moment to regulate a power slope. The application uses a vector power analysis mechanism to capture a load fragmentation signal, eliminates hydraulic hysteresis of a control loop, ensures that a negative pressure release rate of a pipeline matches a load displacement increment, and improves regulation accuracy under a load impedance step working condition.

This invention relates to the field of fault testing technology, specifically to a method for monitoring inter-turn short circuits in dry-type air-core reactors based on the magnetic field difference method. This method constructs a reference electromagnetic coupling matrix by introducing regularization constraints in the initial baseline stage. Based on the recursive analysis of the three-phase current energy thermal accumulation index, it combines the magnetic field residual to fit a thermally induced magnetic field drift model. By combining the joint constraints of the reference electromagnetic coupling matrix and the thermal drift model, the normal thermally induced magnetic field drift component is dynamically removed during real-time monitoring. Under the constraints of the reference electromagnetic coupling matrix, the current vector is optimized through weighted least squares state estimation. The structural consistency deviation index is obtained by comprehensively considering the dual-dimensional deviations of the magnetic field and current for fault monitoring. This invention balances linear electromagnetic transfer laws with nonlinear thermal drift compensation for monitoring, adapting to the complex magnetic field environment and variable load operating conditions of dry-type air-core reactors, providing continuous and reliable monitoring assurance for the long-term stable operation of the equipment.

The invention discloses a method and a device for calculating short-circuit current of an electric power system, a medium and a terminal, relates to the technical field of short-circuit current calculation of the electric power system, and mainly aims to solve the problem that the short-circuit current of a multi-source heterogeneous electric power system cannot be accurately calculated in the prior art. Comprising the following steps: simulating a short-circuit fault in a simulation environment of a target power system, and constructing a non-fault node admittance matrix; calculating an initial current value of each power supply node to obtain an initial system-wide node injection current vector of the target power system, calculating a quotient between the initial system-wide node injection current vector and a non-fault node admittance matrix to obtain a first iteration system-wide node voltage vector of the target power system, and constructing an iteration solution equation; and performing iterative solution on the basis of the iterative solution equation until a preset convergence condition is met, obtaining a full-system node voltage vector after iteration is completed, and calculating the short-circuit current of the target power system according to the full-system node voltage vector after iteration is completed.

The application provides a motor open-phase detection method and related equipment. The method comprises the following steps: obtaining the amplitude of the current vector of the motor, and determining whether the current is a large current or a small current according to the amplitude; for the case that the current is a large current, performing open-phase detection on the motor based on the integral of the amplitude of the current vector; for the case that the current is a small current, performing open-phase detection on the motor based on the polarity of the current. The method can distinguish between the large current and the small current according to the amplitude of the current without introducing other hardware, and then select different open-phase detection methods of the motor, thereby ensuring the accuracy and pertinence of the open-phase detection of the motor.

The application belongs to the technical field of integrated circuits, and discloses a circuit structure for one-step solution of linear equations based on a memristor array, wherein the linear equations are Ax=b, and in the circuit, a first memristor array matrix operation core realizes mapping of the matrix A, takes a negative value of a first operation voltage vector as a bit line voltage, performs a matrix multiplication operation, reads a word line current as a first operation current vector after the operation, a bias mapping module maps b into a bias current vector, a current superposition module superimposes the first operation current vector and the bias current vector to generate a superimposed current vector, and converts the superimposed current vector into a second operation voltage vector through a transimpedance amplifier module, a second memristor array matrix operation core realizes mapping of the matrix A, takes the second operation voltage vector as a bit line voltage, performs a matrix multiplication operation, reads a word line current, and performs an integral operation on the word line current through an integrator module to obtain an updated first operation voltage vector. T The above hardware circuit can realize solution of the linear equations.

The present invention discloses a control method for an internal permanent magnet synchronous motor (MTPA) using virtual signal injection. The method specifically comprises the following steps: Step 1: establishing a mathematical model of the electromagnetic torque after injecting a virtual DC signal; Step 2: calculating the partial derivatives of the electromagnetic torque and the angle between the stator current vector and the d-axis using the electromagnetic torque mathematical model obtained in Step 1; and Step 3: calculating the d-axis and q-axis stator current setpoints using the partial derivatives of the electromagnetic torque and the angle between the stator current vector and the d-axis obtained in Step 2. The present invention solves the problem that conventional virtual injection methods ignore the high-order partial derivatives of the torque and the angle between the current vector and the d-axis, causing the MTPA current trajectory to deviate from the optimal trajectory.

The invention discloses a DC micro-grid power buffer safety control method and device aiming at FDI attack, and relates to the technical field of power electronics and power system control. The method comprises the steps of obtaining a block matrix of a DCmGs system node current equation according to the Kirchhoff's current law; adopting Kron simplification to eliminate internal node voltage, obtaining a relation between a port current vector and a voltage vector, and constructing a small signal model of the port voltage vector; based on a small signal model, a linear mapping relation about disturbance of bus voltage to equivalent input impedance of each power buffer is constructed, modeling and linearization are carried out on energy and adjustable input impedance of each power buffer, a network coupling small signal model is constructed, and a second-order high-gain observer is designed; and if the FDI attack exists in the DCmGs system, an anti-FDI attack elastic control law is designed, so that the closed-loop voltage in the DCmGs system and the energy of a power buffer are quickly converged, and buffeting is inhibited. By adopting the method, the DCmGs system can be prevented from buffeting in an unknown FDI attack scene.

The invention relates to a space vector modulation method based on a single-phase parallel current source inverter, and the method comprises the following steps: 1, constructing a single-phase parallel current source inverter circuit, and dividing all current vectors of the single-phase parallel current source inverter according to different amplitudes of output current Iw; 2, analyzing the influence of the small-current vector redundant switching state on the direct current, and constructing a small-current vector switching state selection strategy; 3, analyzing the influence of the zero-current vector redundant switching state on the direct current, and constructing a zero-current vector switching state selection strategy; and step 4, in each sampling period, synthesizing a reference current vector Iref by two static current vectors which are closest to each other according to an ampere-second balance principle, collecting a power grid voltage us and direct currents i1-i4 at the same time, and selecting a redundant switch state according to the strategies in the step 2 and the step 3 to realize the current balance of the direct current bridge arm. According to the invention, the waveform quality of the grid-connected current can be improved.

A drive device (4) for driving an AC motor (1) by an inverter (11) comprises: a current detection unit (12) for detecting a current flowing through an AC motor; a rotor position calculation unit (14) for calculating rotor position information that represents the position of a rotor included in the AC motor; a voltage command determination unit (15) for determining a voltage command on the basis of the current vector of the current and the rotor position information; a beat-less control unit (18) for suppressing the pulsation of a current caused by the periodic pulsation of a DC bus voltage by operating the voltage phase of the voltage command; and a resonance detection unit (20) for detecting the inductor-capacitor resonance between the inverter and an AC power supply (5) for supplying power to the inverter. The beat-less control unit reduces the operation amount of the voltage phase when the inductor-capacitor resonance is excited.