34 results about "Circuit equation" patented technology

The invention discloses a photovoltaic grid-connected converter impedance modeling method considering frequency coupling, and the method comprises the steps: S1, carrying out the equivalence of a DC side of a grid-connected converter according to the structure of the grid-connected converter, and building a main circuit equation according to a main circuit topological structure; s2, establishing a transfer function expression under frequency disturbance for the phase-locked loop according to a frequency coupling phenomenon caused by asymmetric control of the phase-locked loop; s3, according to the voltage disturbance relation, response relational expressions after voltage disturbance is applied to the alternating-current side and the direct-current side are worked out respectively; and S4, based on the mathematical expressions of the output power, the equivalent admittance and the disturbance admittance obtained in the steps S1, S2 and S3, establishing the equivalent admittance / impedance of the photovoltaic power generation system. According to the method, multi-time scale control and full-working-condition frequency domain port characteristics of the photovoltaic power generation system can be effectively represented, and the equivalent impedance model can accurately analyze the stability of the system.

The invention belongs to the technical field of power system faults, and discloses a turn-to-turn short circuit fault deduction method, system, equipment and medium, and the turn-to-turn short circuit fault deduction method comprises the steps: determining the critical strain value of the fracture of an insulating material based on the axial and radial tensile test data of a winding, and building a mechanical characteristic database of the dependent variable and the insulation fracture; establishing a Poisson boundary value equation set according to the magnetic vector potential and the current density, solving to obtain the magnetic induction intensity, establishing a circuit equation in a short circuit state based on the primary side voltage of the winding, and analyzing the linear relation between the deformation state of the winding and the electromagnetic load to obtain the maximum axial and radial deformation quantity of the winding; and based on the mechanical characteristic database, the turn-to-turn insulation state and the turn-to-turn short circuit condition are judged by combining the axial and radial maximum deformation quantity of the winding. According to the method, when the winding deformation is small, the occurrence condition of the turn-to-turn short circuit fault can be accurately deduced.

The invention relates to a modeling method, an analysis method, a device and a medium for the overall impedance of a new energy field station containing a network construction converter, and the modeling method is based on a harmonic linearization method, and comprises the steps: carrying out the modeling according to a main circuit equation, a power outer loop and a voltage and current inner loop control equation of the network construction converter; and then the frequency coupling characteristic is combined, the converter and the power grid are regarded as a whole, and the overall impedance model of the new energy grid-connected system containing the network-forming converter is obtained. The method can accurately characterize the overall frequency domain characteristics of the grid-forming converter system under the influence of power grid impedance, and is suitable for stability analysis of a grid-connected system.

The present invention discloses a method and device for sequence impedance modeling of a network-forming converter, belonging to the technical field of power system control. The method includes: adding voltage disturbances to the AC port and DC port in the equivalent two-port network of the network-forming converter to be analyzed and modeled; performing frequency coupling analysis on the non-linear circuit under the current response of the voltage disturbance to model the initial transfer function of the sequence impedance model corresponding to each frequency coupling component, fully considering the interaction between network-forming converters, revealing the frequency coupling law of the converter, and improving the accuracy of the sequence impedance model; using the control equation of the network-forming control loop model corresponding to the control loop sequence impedance to remove the zero-sequence component in the circuit equation of the non-linear circuit to obtain a modified sequence impedance circuit equation, which can reduce the complexity of modeling calculation; using the modified sequence impedance circuit equation to modify the initial transfer function of each sequence impedance model to accurately perform linearized modeling of the sequence impedance of the network-forming converter.

The invention discloses a method for analyzing influence factors of current sharing capability of a parallel secondary winding of a CLLLC resonant converter. The method comprises the following steps of: obtaining an equivalent circuit diagram from a parallel secondary winding topology of the CLLLC resonant converter; obtaining resonance current of the two parallel windings based on the equivalent circuit diagram; based on the resonance current, combining the working frequency of a resonant cavity, analyzing the current sharing capability influence factors of the parallel secondary winding, and obtaining a preliminary analysis result; simulating the equivalent circuit diagram to obtain a simulation waveform; and obtaining a final analysis result based on the simulation waveform and the preliminary analysis result. According to the method, a circuit equation is greatly simplified through reasonable order of magnitude approximation, the calculation efficiency is improved while the precision is guaranteed, the method has remarkable circuit design guidance value, and finally the correctness of the scheme is verified through interaction of theories and simulation.

The application provides an asymmetric short-circuit current calculation method and system for large-scale new energy stations, and the method comprises the following steps: judging a fault type and a fault phase; constructing a fault composite sequence network; calculating negative sequence impedance of each new energy station, and calculating positive sequence initial voltage of each new energy station; calculating output short-circuit current of each new energy station; obtaining a simplified equivalent circuit through circuit simplification according to the fault composite sequence network; calculating positive sequence voltage of each new energy station; comparing the positive sequence voltage of each new energy station with the positive sequence initial voltage, judging whether a voltage difference meets convergence accuracy, solving output negative sequence current and zero sequence current of each new energy station according to a circuit equation; and outputting output phase current of each new energy station. The application overcomes the influence of a converter control on a phase selection element, can effectively shorten the iteration number, avoids the process of solving matrix inverse operation by using a node voltage method, has good engineering practicability and precision, and can be applied to large-scale new energy stations.

The invention discloses an electromagnetic network coupling analysis method and system based on a discontinuous Galerkin technology, and the method employs the network parameter-S parameter of an external circuit to represent a complex circuit network, and achieves the coupling between an electric field and a circuit. A numerical flux suitable for frequency domain field-circuit coupling is derived, and a frequency domain field-circuit joint simulation model is established. According to the method, co-simulation of an electromagnetic field and a circuit system is supported, a field equation and a circuit equation can be directly coupled by enabling a circuit to be equivalent to an S parameter of the circuit, errors caused by traditional step-by-step solving are avoided, and the calculation efficiency is improved while the calculation precision is guaranteed.

This invention discloses a method and terminal for overcurrent modeling of a power supply system. It establishes an equivalent circuit model of the DC bus transmission line during short-circuit transients using an R-C-L model to represent the DC network power transmission line. A fuse model is placed near the lithium-ion battery in the equivalent circuit model, and the fuse's melting process is divided into a pre-arc process and an arcing process. During the pre-arc process, the fuse's inductance is ignored, and it is equivalent to a variable resistor. Circuit equations for the pre-arc process are established, along with arcing conditions. During the arcing process, the arc initiation model is equivalent to a variable resistor in series with a voltage source. Dynamic circuit equations for the arcing process are established, along with fault judgment conditions and fuse melting conditions. Based on the equivalent circuit model and the fuse model, a system model of the power supply system is constructed. This invention establishes a more accurate system model, enabling more effective modeling and simulation.

The application discloses a kind of MMC bipolar system direct current impedance modeling method and related device, belong to electrical engineering field, the modeling method has integrated alternating current coupling, control strategy dynamics and multi-frequency harmonic interaction by state space equation, the harmonic state space modeling framework presented can accurately analyze the influence of harmonic on direct current impedance, provides theoretical basis for system resonance suppression under weak power grid scene, the influence of the coupling part on circuit equation and modulation ratio transfer function in the AC side of converter station in bipolar system is considered, the state space equation of entire converter station is obtained;Using the relationship between input variable and state variable in harmonic state space equation, finally the direct current impedance matrix of bipolar system converter station is extracted, the modeling method presented in the application considers the generation mechanism of coupling impedance, establishes accurate mathematical model to characterize high-voltage direct current transmission system, lays an important foundation for stability analysis of the direct current side of converter station.

A wireless power transfer (WPT) online parameter identification method based on a BP neural network comprises the steps of designing a multi-level parameter combination table of a mutual inductor M and a load RL in combination with an actual wireless charging system circuit topology, and performing model simulation calculation according to parameter design in the parameter combination table to obtain system state data; in combination with simulation data, establishing and training a BP neural network by using a neural network function in numerical simulation software to obtain a WPT system parameter online identification model; and required state quantities are acquired from an actual system and are input into the recognition model for calculation, so that real-time parameter recognition of the WPT is completed. According to the method, additional communication equipment or auxiliary circuits do not need to be added, the design difficulty and cost are low, and the influence on the working state of the system is low. The method has the advantages that a complex circuit equation does not need to be calculated, errors are corrected through circuit actual measurement data, parameter identification errors are effectively reduced, and the requirement for WPT online parameter identification is met.

The application discloses a kind of energy storage converter asymmetric fault analysis methods based on virtual synchronous machine technology, using the vector control strategy based on internal potential orientation, grid-connected point voltage is separated into positive and negative sequence;According to asymmetric fault scene adjustment control link, including using trap filter to filter out the two-frequency fluctuation component in inverter output power, the reference voltage in reactive-voltage loop is switched from rated voltage to grid-connected point positive sequence voltage, negative sequence is inhibited by balance current strategy;Based on reactive-voltage circuit equation and reactive-voltage control equation, establish the equation about internal potential;According to virtual impedance ring control equation, calculate current reference value before fault and substitute into the virtual impedance ring control equation after Laplace transform, establish the equation about fault current dq axis component;According to the equation about internal potential and the equation about fault current dq axis component, construct the analytical expression of fault current.The application considers the influence of inverter control link on fault current transient characteristic, and analytical precision is high.

The present invention discloses a field-circuit coupling numerical calculation method for the internal magnetic field distribution of a converter transformer, which relates to the field of electromagnetic field and circuit coupling simulation. The method includes: collecting system parameters to construct a set of design variables, uploading them to the cloud for processing; establishing a temperature-dependent magnetic permeability and frequency-dependent conductivity model; simulating the mutual influence between current, voltage and magnetic field by solving the field-circuit coupling equation and the circuit equation; using multi-objective optimization to calculate the magnetic field uniformity index and total loss, and updating the design variables; correcting the simulation model by comparing with the measured data, and updating the temperature-dependent magnetic permeability and frequency-dependent conductivity model until the error is less than a threshold. By combining the temperature-dependent magnetic permeability and frequency-dependent conductivity models, using a multi-objective optimization method, and adjusting the simulation model in real time, higher simulation accuracy, improved system performance and design adaptability are achieved, thereby improving the efficiency, stability and accuracy of the converter transformer.

The invention discloses an MMC bipolar system direct current impedance modeling method and a related device, and belongs to the field of electrical engineering. The modeling method integrates alternating current circuit coupling, control strategy dynamic and multi-frequency harmonic interaction through a state-space equation; a proposed harmonic state space modeling framework can accurately analyze the influence of harmonic waves on direct current impedance, a theoretical basis is provided for system resonance suppression in a weak power grid scene, the influence of a converter station alternating current side coupling part in a bipolar system on a circuit equation and a modulation ratio transfer function is considered, and a state space equation of the whole converter station is obtained; according to the modeling method provided by the invention, the generation mechanism of coupling impedance is considered, an accurate mathematical model is established to represent the high-voltage direct-current power transmission system, and the high-voltage direct-current power transmission system has the advantages that the high-voltage direct-current power transmission system can be constructed; and an important foundation is laid for stability analysis of the DC side of the converter station.

The present invention provides a real-time solution method, system, device and medium for circuit equations based on micro-momentum. Based on the concept of "small changes, no changes", according to the characteristics of actual power electronic systems with numerous switches, different influence weights of each switch, and the rapid decrease in the influence of a single switch as the number of system switches increases, the method analyzes the impact of switch switching on circuit equations and their solutions. The maximum number of simulation steps and the maximum allowable error can be set. The relationship between accuracy and speed is established through the maximum number of simulation steps and the maximum allowable error, thereby obtaining a standard for accuracy and speed selection, so that the solution accuracy and solution speed of the circuit equation solution algorithm are coordinated and controllable.

The present invention discloses a PWM average current calculation device and method for a proportional solenoid valve. Its acquisition module acquires the power supply voltage, the peak and valley drive currents of the spool and the corresponding moments; the parameter calculation module calculates parameters such as the inductance and resistance of the proportional solenoid valve coil; the filter module performs low-pass filtering on the coil inductance and resistance; the current refinement module calculates the time constant, establishes the corresponding circuit equation, and calculates the refined current value to determine the current sequence; the average current module performs trapezoidal summation on the current sequence and then divides it by the PWM period to calculate the average current. The present invention not only has the advantage of calculating the average current through software, but also has the advantages of reducing the sampling frequency, reducing costs, improving the calculation accuracy, thereby improving the spool control accuracy, enhancing the rapidity and stability of current control, etc., which is beneficial to eliminating the changes in the resistance of the proportional solenoid valve caused by changes in environmental factors, increasing the adaptability, and at the same time enhancing the responsiveness of the proportional solenoid valve.

The invention discloses a field-circuit coupling method and device based on a time domain hybrid finite element method and a delay insertion method. The method comprises the following steps: discretizing a three-dimensional electromagnetic structure through a tetrahedral mesh, reading the port characteristics of an IBIS model, constructing an electromagnetic field equation based on a hybrid finite element algorithm of tree-cotree decomposition, and reducing the order through a modal order reduction technology after discretization; an electromagnetic port is equivalent to a series structure, the series structure is coupled with an IBIS model equivalent circuit to construct an EM-IBIS system, and a circuit equation is solved through an LIM method; a self-adaptive local time step length strategy is adopted, an electromagnetic part adopts large-step-length propulsion, and a circuit part is subjected to self-adaptive subdivision iteration in each electromagnetic step length until a convergence condition is met. Simulation precision and efficiency are balanced, full-link simulation is supported, the design reliability of a high-speed and high-density electronic system can be improved, and the method has important application value in scenes such as signal integrity, power supply integrity and electromagnetic compatibility optimization.

This invention relates to a rapid calculation method for loop parameters of a high-voltage power supply and utilization experimental device, belonging to the technical field of short-circuit breaking tests for large-capacity high-voltage electrical appliances. The method employs a direct method using the output of an impulse generator to establish the corresponding test loop circuit topology, simplifying it to a single-phase equivalent calculation circuit with the first open pole. Based on this circuit, a third-order circuit equation for the TRV waveform to be solved is established. For the third-order circuit equation of the waveform, engineering simplification conditions are substituted to simplify it into a series discharge solution, yielding simplified and per-unit solutions. The equations for the simplified and per-unit solutions are then dimensionless, reducing their dimensionality. Based on the dimensionless equation of the dimension-reduced waveform, the test voltage, dimensionless parameters, and peak time are substituted sequentially to calculate the initial values ​​of the device loop parameters. This invention can significantly improve the efficiency of short-circuit breaking tests in large-capacity test stations.

The invention provides a simulation training system for a secondary circuit of a power system and a working method of the simulation training system. The simulation training system comprises a simulation construction module, a circuit calculation engine, a virtual tool module and a defect simulation module. Wherein the simulation construction module is used for constructing a target secondary circuit simulation model comprising a terminal strip and multiple components. According to the circuit principle, a circuit equation is constructed and solved, node potentials are calculated, and component states are iteratively updated, so that the dynamic working process of a loop is simulated. Wherein the virtual tool module provides at least one virtual maintenance tool for a user to measure or operate the simulation model and perform loop state diagnosis or defect repair. Wherein the defect simulation module is used for presetting at least one type of circuit defect in the simulation model and creating a fault scene for training.

The invention discloses a method for estimating the real-time short-circuit capacity of a superior common connection point of a bilateral traction power supply system, and aims to effectively solve the technical problem that the short-circuit capacity of the superior common connection point of the bilateral traction power supply system cannot be calculated in real time. And solving the real-time short-circuit capacity of the superior power grid of the traction power supply system in combination with system electrical structure characteristics. The method comprises the following steps: step 1, listing circuit equations of a branch 1 and a branch 2; 2, listing a circuit equation of a branch 3; 3, estimating the short-circuit capacity of the node 3; and step 4, estimating the superior short-circuit capacity.

The invention discloses a field-circuit coupling numerical calculation method for internal magnetic field distribution of a converter transformer, and relates to the field of electromagnetic field and circuit coupling simulation. The method comprises the steps of collecting system parameters to construct a design variable set, and uploading the design variable set to a cloud for processing; establishing a temperature-dependent magnetic conductivity and frequency-dependent conductivity model; simulating the mutual influence among the current, the voltage and the magnetic field by solving a field-circuit coupling equation and a circuit equation; calculating a magnetic field uniformity index and total loss by adopting multi-objective optimization, and updating a design variable; and the simulation model is corrected by comparing with measured data, and the temperature-dependent magnetic conductivity and frequency-dependent conductivity model is updated until the error is smaller than a threshold value. According to the method, temperature-dependent magnetic conductivity and a frequency-dependent conductivity model are combined, a multi-objective optimization method is adopted, and a simulation model is adjusted in real time, so that higher simulation precision, system performance improvement and design adaptive capability are realized, and the efficiency, the stability and the precision of the converter transformer are improved.

The invention provides an SRM (switched reluctance motor) non-inductive control method based on a self-adaptive superspiral sliding-mode observer, and the method comprises the following steps: obtaining a phase current, a phase voltage and a rotor position estimation value of a switched reluctance motor, calculating a phase flux linkage value according to the phase current and the phase voltage, obtaining an estimated phase current value according to the phase flux linkage value and the rotor position estimation value, and calculating the phase flux linkage value according to the estimated phase current value. According to a circuit equation, a mechanical equation and an estimated phase current value of the switched reluctance motor, a sliding mode surface function of the super-spiral sliding mode observer is constructed, and according to the sliding mode surface function, the super-spiral sliding mode observer is constructed by adopting a second-order sliding mode reaching law to estimate the rotor position of the switched reluctance motor. And after the super-spiral sliding-mode observer is simplified, compensation is carried out to obtain a compensated super-spiral sliding-mode observer, the compensated super-spiral sliding-mode observer is adopted to estimate the rotating speed and the position of the switched reluctance motor, and an estimation result is further optimized in combination with adaptive control. And the robustness, the accuracy and the dynamic performance of the position estimation of the switched reluctance motor are improved.

The present application relates to the technical field of lithium ion battery state estimation, in particular to a low-temperature lithium battery SOC estimation method based on PIKAN-LSTM, which firstly carries out low-rate discharge test under multiple temperature environments, constructs the relationship curve of open-circuit voltage, state of charge and temperature, and completes the training and verification of the first KAN model; then builds a PIKAN model containing a circuit equation solving unit and a second KAN network unit, identifies the battery equivalent resistance and two-stage polarization voltage in combination with the second-order RC equivalent circuit equation; then obtains the estimated open-circuit voltage through voltage compensation operation, inputs the first KAN model to output the preliminary state of charge; finally, the time series error correction is carried out by using the bidirectional LSTM network to obtain the final estimation result, which effectively solves the problems of battery model parameter drift and estimation error accumulation under low-temperature working conditions, and significantly improves the estimation accuracy and robustness.

The application relates to the technical field of wireless power supply, in particular to a multi-relay wireless power supply system modeling method, which comprises the following steps: S1, constructing a circuit equation based on an impedance matrix according to the circuit topology of the multi-relay wireless power supply system, and performing LDU decomposition on the impedance matrix of the system to obtain a lower triangular impedance matrix, a diagonal impedance matrix and an upper triangular impedance matrix; S2, performing forward voltage transformation according to the lower triangular impedance matrix and a system input voltage phasor; S3, solving forward current according to the diagonal impedance matrix and the forward voltage; S4, performing backward current transformation according to the upper triangular impedance matrix and the forward current to solve loop currents of the multiple relay coils. The method can clearly describe the cross-coupling relationship between the coils of the multi-relay wireless power supply system, can decompose the coil composition of each loop, and can be used for analyzing the input, output and other characteristics of the multi-relay wireless power supply system under complex cross-coupling.

The invention relates to the technical field of power electronic simulation, in particular to a hardware description language model generation method and system. The generation method comprises the following steps: acquiring elements and nodes in a circuit topology file; the elements are converted into an equivalent circuit model, an admittance matrix is constructed, and a circuit equation resolving matrix is obtained; calling a preset operator module to replace calculation elements in the circuit equation solution matrix to obtain a core calculation unit; constructing a model input unit and a model output unit; and integrating the units according to a preset top template to obtain a hardware description language model. Complex matrix operation is achieved through the standardized operator module, conversion from circuit topology to a mathematical model is completed, the tedious process of manual coding matrix operation is avoided, the development difficulty is low, the development time is short, and errors are not prone to occurring.

The present invention proposes an active detection cable fault location method based on a controllable converter, comprising: when a fault occurs, controlling the controllable converter to output two sinusoidal voltages of different preset frequencies; obtaining the voltage and current phasors at the head end of the cable line at the two preset frequencies, and using the voltage and current phasors to construct a set of circuit equations from the head end of the cable to the fault point; and solving the set of circuit equations simultaneously to obtain the fault distance from the fault point to the head end of the cable. This method does not require additional pulse injection equipment or communication between the two ends of the cable. It is suitable for metallic faults and high-resistance faults, has strong anti-interference capabilities, and is computationally simple. While ensuring accurate and reliable fault location, it can be implemented based on existing cable configurations, reducing implementation costs.

The invention relates to a distributed photovoltaic new energy aggregation overall impedance modeling method and device.The modeling method is based on a harmonic linearization method, modeling is conducted according to a photovoltaic inverter main circuit equation, a power outer loop and a voltage and current inner loop control equation, and a photovoltaic inverter impedance model considering frequency coupling is obtained; and the inverter and a power grid are regarded as a whole by combining frequency coupling characteristics, and an overall impedance model of the new energy grid-connected system containing the photovoltaic inverter is obtained. The method can accurately characterize the overall frequency domain characteristics of the photovoltaic inverter system under the influence of power grid impedance, and is suitable for stability analysis of a grid-connected system.

The present invention discloses a sequence immittance modeling and stability analysis method for a heterogeneous renewable energy grid-connected power system, belonging to the field of power system control technology. The method performs two-port equivalence on various converters in the heterogeneous renewable energy grid-connected power system and adds voltage disturbances to the AC port and the DC port; further, the control loops and nonlinear circuits of the various converters under the current response of the voltage disturbance are modeled to obtain the initial transfer function of the sequence immittance model corresponding to each frequency coupling component, fully considering the interaction between the grid-connected / connected converters, revealing the frequency coupling law of the converter, and improving the accuracy of the sequence immittance model; then, the corrected sequence immittance circuit equation is used to correct the initial transfer function of the sequence immittance model corresponding to each frequency coupling component, to obtain the corrected transfer function of the sequence immittance model of each frequency coupling component, and accurately perform linear modeling on the sequence immittance of the heterogeneous renewable energy grid-connected power system.

This invention discloses a method and terminal for simulating overcurrent in a power supply system. It establishes an equivalent circuit model of the DC bus transmission line during short-circuit transients using an R-C-L model to represent the DC network power transmission line. A fuse model is placed near the lithium-ion battery in the equivalent circuit model, and the fuse's melting process is divided into a pre-arc process and an arcing process. During the pre-arc process, the fuse's inductance is ignored, and it is equivalent to a variable resistor. Circuit equations for the pre-arc process are established, along with arcing conditions. During the arcing process, the arc-initiating model is equivalent to a variable resistor in series with a voltage source. Dynamic circuit equations for the arcing process are established, along with fault judgment conditions and fuse melting conditions. Based on the equivalent circuit model and the fuse model, a system model of the power supply system is constructed. This invention establishes a more accurate system model, enabling more effective modeling and simulation.

The application relates to the technical field of power system modeling, in particular to an impedance network modeling method and device for an AC-DC hybrid system, wherein the method comprises the following steps: establishing impedance models of various power devices in the AC-DC hybrid system, and establishing an admittance matrix of AC network nodes except for a converter; and obtaining an impedance network model of the AC-DC hybrid system by establishing an admittance matrix of an AC system containing the converter and a multi-port model of a DC network. According to the embodiment of the application, the impedance model can represent the dynamic characteristics of the devices by circuit equation connection, and the voltage-current relationship of the system nodes is established, so that the impedance network model capable of representing the overall dynamic characteristics of the system is obtained, the modeling method can be applied to large-scale actual AC-DC hybrid system modeling, is favorable for oscillation mechanism analysis, the universality and comprehensiveness of the modeling method are enhanced, and the modeling result is more reliable.

According to various embodiments of the present disclosure, a method for solving circuit equations of a processing element (PE) using a neural network by a graphic processing unit (GPU) comprising: forming M aligned virtual cell arrays in the neural network, wherein the cell arrays have a height value N and a width value O, each virtual cell array corresponding to a crossbar array circuit included in a processing element; performing 3D convolution on each of the virtual cell arrays until the height value N of each of the virtual cell arrays becomes 1; inputting parameters of the memory cells of the crossbar array to each of the virtual cell arrays in which the three-dimensional convolution is performed; and solving a circuit equation of the processing element using the output value of the virtual cell arrays.