33 results about "Vector potential" patented technology

The invention provides a motion simulation method and system for charged particles in a magnetic field, and the method comprises the steps: substituting the magnetic vector potential of an electromagnetic field where the charged particles are located into an established kinetic equation, solving the kinetic equation, and obtaining the motion trail of the charged particles; the kinetic equation is a Hamiltonian equation corrected by a narrow relativistic added with Lorentz force. The method has the advantages that a more comprehensive simulation method for the movement of the charged particles in the electromagnetic field is constructed, a simulation model based on energy conservation is considered, the divergence behavior of long-period prediction of a simulation system is improved, and long-period and high-precision simulation of the high-speed charged particles in the earth magnetic field is achieved.

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 an in-hole transient electromagnetic response characteristic numerical simulation method based on a tunnel three-dimensional geoelectric model and an absorption boundary finite element method, and belongs to the technical field of geophysical exploration. The method comprises the following steps: constructing a tunnel full-space three-dimensional conductivity model; based on a Maxwell equation set, a vector potential and a scalar potential are introduced, a vector control equation of a transient electromagnetic field is derived in combination with Coulomb specifications, first-order absorption boundary conditions are established, and a weak form finite element equation is derived through a Galerkin weighted margin method; generating a global sparse matrix by utilizing spatial discretization and unstructured grid division, and performing iterative solution on the dynamic electromagnetic field by adopting a Newmark time discretization method; and simulating the transient electromagnetic response of geological anomalous bodies with different resistivity and the distance between the geological anomalous bodies and the receiving coil, and analyzing the attenuation characteristic and the geometric gravity center effect to obtain an electromagnetic response rule. The device can accurately simulate the electromagnetic response of abnormal bodies such as aquifers and faults in front of a tunnel face and around drill holes.

This invention discloses a method for calculating electromagnetic anomalies in fracturing fractures of a charging conductor, comprising the following steps: S1, establishing a fracture model by monitoring the well location, burial depth, fracture size, power supply current, and frequency settings; S2, calculating the formation equivalent resistivity using multi-layer profile parameters; S3, dividing the charging conductor into Nd electric dipole sources and obtaining the vector potential and scalar potential Φ of each electric dipole source at the surface; S4, obtaining the E and H values ​​of the electric dipole sources at the surface according to the electric field and magnetic field calculation formulas, determining the reference point N, and obtaining the electric field E in the MN direction. MN and magnetic field H MN S5. Based on the principle of vector superposition, the electromagnetic fields of all the segmented electric dipole sources are superimposed to obtain the electromagnetic fields before and after fracturing, and the electric field anomaly E caused by the fracturing fracture is obtained by differential calculation. a and magnetic field anomaly H a The present invention aims to construct a model of a charging conductor crack to obtain electromagnetic anomalies generated by fracturing cracks, providing a theoretical basis for electromagnetic monitoring and crack identification.

The application provides a kind of multi-element rotating circularly polarized yagi antenna analysis method and its five-element structure related to the technical field of antenna, comprising the following steps: S1, establishing antenna model and analyzing magnetic vector potential and scalar potential;S2, electric field double-bit integral equation is established;S3, based on the theory of moment method, the integral equation to be solved is discretized;S4, impedance matrix is solved, and then far-field electric field is obtained;S5, the expression of far-field electric field is expanded, considering the rotating oscillator unit vector, the linear antenna array electric field calculation formula of rotating oscillator is obtained;S6, according to the formula of circularly polarized pattern, the polarization pattern is calculated and compared with simulation;S7, a five-element structure is designed according to the theory and the performance is analyzed.The application calculates the three-dimensional spatial arrangement of the oscillator rotation, and the conclusion obtained effectively explains the reason why the axial rotating antenna array generates circularly polarized wave, and provides better theoretical support for antenna design.

The invention relates to the field of high-speed magnetic levitation electromagnetic braking, and particularly discloses a linear eddy current braking system applied to electric high-speed magnetic levitation and having normal force restraining and braking force improving effects, and the linear eddy current braking system comprises the steps that S1, a PHE-LECB system is constructed, and a two-dimensional simplified model of a pair of poles of the PHE-LECB system is established; s2, establishing a magnetic vector potential partial differential model according to the two-dimensional simplified model of the pair of poles of the PHE-LECB system established in the step S1; s3, sub-domain magnetic field boundary condition analysis is carried out after the magnetic vector potential partial differential model established in the S2; s4, establishing a flux density distribution and electromagnetic force model according to S2 and S3, and obtaining total braking force and normal force of the system; and S5, establishing a finite element model of the PHE-LECB system, and verifying the correctness of the analytical model. According to the method, eddy current normal force is effectively restrained, stable suspension of the EDS maglev train during emergency braking is guaranteed, eddy current braking force is further improved, shorter emergency braking time can be brought to the train, and operation safety is effectively guaranteed.

The invention discloses an automatic sparse data labeling method and system based on a graph neural network, and the method comprises the steps: constructing a space-time diagram structure, carrying out the embedding and mapping of traffic flow and speed features through a Grassmann manifold, and generating node features and edge weights; constructing a traffic flow field based on the node features and the edge weights, decomposing the traffic flow field into diffused gradient features and direction-changing curl features, and updating the edge weights; designing a drawing convolution mechanism, and fusing scalar potential and vector potential convolution kernels to generate a propagation kernel; constructing a space-time propagation mechanism through a long and short-term memory network to update node features; a dynamic action range is introduced, and a propagation range is adjusted by combining node density and a traffic flow field; the traffic flow field is used as a confidence index, traffic flow information of marked nodes is spread to sparse nodes through a Poisson equation, and high-precision automatic marking is achieved; the method overcomes the limitation that a traditional method neglects nonlinear dynamic and static propagation, can improve the precision and robustness of sparse node labeling, and is suitable for peak and emergency scenes.

The application provides a kind of electromagnetic field fast prediction method and system of maglev train suspension electromagnet, for the coil strong source of suspension electromagnet under typical working condition, nonlinear constitutive of iron core and local high gradient multiscale coupling problem, based on electromagnetic field sample data extraction coil area and construct distance field, according to the structure characteristics of suspension electromagnet and the distance field, the solving area of electromagnet is divided into coil conductor subdomain and multiple iron core subdomains of different distance levels, and subnetwork is respectively constructed.In the training process, the residual error of Maxwell quasi-static equation and the consistency constraint of material constitutive are introduced in the subdomain, the magnetic vector potential continuity and the normal continuity constraint of magnetic induction intensity are applied on the interface of subdomain;Further introduce the time-varying mixed scheduling mechanism of the right end source term of iron core subdomain, to improve the prediction stability and precision of strong source area and high gradient area.In the reasoning stage, the electromagnetic field distribution can be quickly output, and support is provided for fast calculation of electromagnetic force, eddy current loss, etc.

The invention discloses a field-line coupling voltage calculation method and device, electronic equipment and a storage medium, and is used for solving the problems that a current field-line coupling calculation mode cannot effectively avoid discretization errors and is relatively poor in calculation stability. The method comprises the following steps: acquiring electromagnetic field observation data of a lightning channel; respectively solving scalar potential in the electrostatic field and vector potential in the magnetic field according to electromagnetic field observation data; constructing an incident electric field model according to the scalar potential and the vector potential; and according to the incident electric field model, carrying out voltage solving calculation based on the separation potential to obtain the coupling voltage on the transmission line within the influence range of the lightning channel under the lossless grounding condition. Therefore, the dependence on a high-order numerical algorithm is reduced directly through separation solution of the potential and the magnetic potential, the calculation structure can be simplified, the calculation complexity is reduced, the problem of error accumulation possibly introduced in the high-order algorithm is avoided, and higher efficiency and stability are achieved.

The invention discloses a passive shimming method, system and device of a permanent magnet type magnetic resonance imaging system, and belongs to the field of magnetic resonance imaging, and the method comprises the steps: measuring an initial magnetic field, and carrying out the harmonic analysis, and obtaining an initial harmonic coefficient; obtaining gasket parameters to enable the nonlinear magnetization correction analysis model to calculate the gasket magnetization intensity of each gasket through the hysteresis model, converting the gasket magnetization intensity into equivalent surface current density through the equivalent surface current model, and performing integral solution on the equivalent surface current density under a cylindrical coordinate system to obtain the gasket magnetization intensity. Obtaining the magnetic vector potential and the magnetic field of each gasket, and carrying out harmonic analysis to obtain a gasket harmonic coefficient; in the passive shimming optimization model, the magnetization thickness function is iteratively updated to obtain a laying scheme when the total weight of the gasket is minimum, and the gasket is laid according to the laying scheme to realize passive shimming, so that higher field uniformity can be realized, the optimization efficiency is improved, and the consumption of the gasket is reduced.

A method for generating a simulation grid of a linear plasma device, which belongs to the field of numerical simulation of linear plasma devices. This method first requires inputting various parameters of coils and measurement points. By judging the distance between the coils and the measurement points, different calculation methods are selected, and then the magnetic vector potential, magnetic flux, magnetic field strength, etc. of each measurement point are calculated. Then, the information of the grid point coordinates is obtained by using the interpolation method. Next, the above data information is stored in a general file format, and finally, the magnetic field information is displayed through a visualization method. This method has the ability to adaptively calculate the grid and supports flexible adjustment of coil parameters, including current, placement position, etc. The characteristics of the present invention lie in the accurate and efficient calculation method, multi-coil combination simulation, intuitive visualization method, and generation of a general grid, bringing a new technical solution to the field of magnetic field analysis and design of linear devices and numerical simulation, and having significant scientific research and engineering application values.

This application proposes a design method for a vehicle-mounted adaptive antenna. This method uses the metal of the vehicle body as the main radiating element of the antenna. Based on the method of moments (MoM), it starts with the magnetic vector potential, calculates the magnetic field, and then uses the magnetic field to calculate the electric field. Finally, it uses Ampere's law from Maxwell's equations to obtain a wave equation based on the magnetic vector potential. The integral relationship between the electric field and the surface current is solved using the wave equation. By observing the surface current distribution and radiation pattern on the vehicle body structure, modes that meet the coverage and feeding requirements are identified, and these modes are excited by feeding. Alternatively, in cases requiring broadband design, excitation can be added to multiple regions with similar surface current distributions to achieve simultaneous excitation of multiple modes, thus realizing a broadband mode antenna design. Since the main radiating element of this antenna is the metal structure of the vehicle body, it has advantages such as ease of implementation, low cost, simple structure, and no space occupation within the vehicle.

This invention provides a numerical simulation method for magnetotellurics under the Lorentz specification. The Maxwell equations are transformed into a set of governing equations consisting only of vector potentials using the Lorentz specification. A two-dimensional Fourier transform is performed on the quadratic vector potential governing equations in the horizontal direction, converting the three-dimensional governing equations into one-dimensional governing equations, reducing computational load and storage requirements, and improving computational efficiency. The Fourier transform can employ the standard Fourier transform algorithm, the offset sampling Fourier transform algorithm, or the non-uniform sampling Fourier transform algorithm. Then, the one-dimensional equations are solved using the one-dimensional finite element method with quadratic interpolation shape functions, resulting in three pentagonal equation sets, which are then solved using the pursuit method. This invention offers fast computation speed and small memory footprint, providing a new method for efficient and high-precision numerical simulation of large-scale magnetotellurics.

The invention discloses an optimal design method for a magnetic coupling mechanism of a wireless energy transmission device, and belongs to the technical field of wireless power transmission. The method comprises the following steps: determining an initialization parameter of the magnetic coupler; constructing a physical information neural network model, and outputting magnetic vector potential distribution of the magnetic coupler; constructing a geometric parameter optimization loss function; calculating the gradient of the geometric parameter optimization loss function to the structure parameter by using an automatic differential technology; iteratively updating the structural parameters by adopting an optimization algorithm according to the gradient; and judging whether the optimization process is converged or not, and if yes, outputting the optimal structure parameter. According to the method, the electromagnetic physical law and the data driving model are combined through the physical information neural network, micro-optimization of the parameters of the magnetic coupler is achieved, and the problems that an existing magnetic coupler design method is high in calculation cost, low in efficiency, insufficient in optimization precision, poor in flexibility and the like are solved.

The application discloses a kind of two-dimensional magnetic field analysis method and system of multilayer cylinder magnetic shielding structure, belong to electromagnetic analysis technical field.The method includes: establishing multilayer cylindrical two-dimensional analytical model, the magnetic field distribution expression of each air domain and magnetic shielding layer is determined;The continuity constraint condition at the inner and outer boundary of magnetic shielding layer is solved, the expression of corresponding reflection coefficient and transmission coefficient is obtained, and it is simplified, and the expression only including shielding layer radius and relative magnetic permeability is obtained;Based on the cumulative influence of incident harmonic amplitude in the transmission process of adjacent two layers of magnetic shielding layer, transmission coefficient is obtained;According to reflection coefficient, transmission coefficient and transmission coefficient, the magnetic vector potential component expression of each air domain is determined, the corresponding magnetic field distribution result is obtained, and magnetic field analysis is carried out.The magnetic vector potential component expression of each air domain of magnetic shielding structure is directly written by self-defined parameter, and the complexity of multilayer structure solving process is reduced.

A method for reconstructing the wavefront of a light beam by analyzing wavefront-gradient data of said light beam, the light beam containing at least one optical vortex, considering the contribution of the optical vortices to the wavefront. The method including providing a phase-gradient map g of the wavefront of the light beam, generating a Laplacian of a vector potential based on the phase gradient map g, the resulting Laplacian of the vector potential map, called “Laplacian map”, exhibiting peaks, the location of each peak corresponding to the location of an optical vortex and the integral of the peak being proportional to a topological charge n of said optical vortex, computing a singular phase map φs based on the topological charge n and location of each optical vortex, the singular phase φs map being representative of the contribution of the optical vortex.

The application relates to a high-precision calculation method of an edge-smoothed edge element static magnetic field based on an MVP formula, which divides grid data into a plurality of polyhedral smoothing domains with corresponding edges as centers according to each edge in the grid data, and the polyhedral smoothing domain is formed by nodes, body centers and face centers of tetrahedral units in the grid data around the corresponding edge; the vector function gradient of the corresponding edge is calculated based on the vector function of each tetrahedral unit in the polyhedral smoothing domain corresponding to the edge; the static magnetic field equation is constructed based on the MVP formula and the Coulomb norm, and the static magnetic field equation is rewritten according to the vector function gradient of each edge and the Galerkin method, so that the system equation of the static magnetic field is obtained; the system equation of the static magnetic field is further rewritten into Newton iteration linear equations; the Newton iteration method is used to iteratively solve the Newton iteration linear equations until convergence, so that the magnetic vector potential in the static magnetic field is obtained. The method realizes the high calculation precision and stability requirement of an engineering static magnetic field problem.

The invention discloses a construction method of a rapid discrete analytical model for pulsed eddy current detection of a metal pipeline, and belongs to the field of electromagnetic nondestructive detection.The construction method comprises the steps that a physical model for pulsed eddy current detection of the metal pipeline is constructed, and a complex frequency domain magnetic vector potential expression in the physical model is determined; for the finite-length metal pipeline, the complex frequency domain magnetic vector potential in the axial interval of the finite-length metal pipeline is expanded into an odd function form through Fourier series, and a magnetic vector potential expression in a discrete form is obtained; a complex frequency domain induced voltage expression of the receiving coil is deduced according to the incidence relation between the electric field intensity and the induced voltage by combining geometric parameters of the receiving coil; the method comprises the following steps: selecting a Fixed-Talbot algorithm, determining free parameters of the algorithm, performing inverse Laplace transformation on a variable containing complex frequency in a complex frequency domain induced voltage expression to obtain a time domain expression of the variable, further obtaining time domain induced voltage of a receiving coil, and completing construction of a metal pipeline pulsed eddy current detection analytical model.

The present application provides a method and system for simulating the motion of charged particles in a magnetic field. The method includes: substituting the magnetic vector potential of the electromagnetic field where the charged particles are located into the established dynamic equation, solving the dynamic equation to obtain the motion trajectory of the charged particles; the dynamic equation is the Hamiltonian equation after the Lorentz force is added with the special relativity correction. The advantages of the present application are as follows: a more comprehensive simulation method for the motion of charged particles in an electromagnetic field is constructed, a simulation model based on energy conservation is considered, the divergence behavior of the long-period prediction of the simulation system is improved, and the simulation of high-speed charged particles in the Earth's magnetic field with high precision over a long period is realized.

The invention discloses an electromagnetic sensor signal analysis method and system based on real abrasive particle dynamic trajectory and time-harmonic field intensity coupling, and belongs to the field of mechanical equipment state monitoring and sensor simulation. The method comprises the following steps: firstly, based on a CFD-DEM coupling theory, combining abrasive particle multi-physical field stress, and accurately reconstructing a real three-dimensional dynamic track in a complex flow field of a lubricating oil pipeline; and establishing a three-dimensional time-harmonic magnetic field analysis model based on magnetic vector potential and a modified Bessel function, constructing a dynamic mapping relation between the transient position of the abrasive particles and a non-uniform magnetic field, quantifying the disturbance characteristic of the abrasive particle eddy current to the magnetic field, and solving the transient response of the sensor induced electromotive force. Abrasive particle size, material conductivity and magnetic conductivity parameter correction are fused, simulation distortion caused by a simplified motion model and neglect of radial magnetic field difference in a traditional theory is overcome, and high-precision prediction of dynamic signals of the whole process that the abrasive particles pass through the sensor is achieved. The method is suitable for health monitoring of aero-engines and industrial gearboxes.

The invention relates to a transient electromagnetic three-dimensional numerical simulation method and device based on an observation decomposition framework. The method comprises the following steps: dynamically and adaptively decomposing an emission source into a plurality of decomposition sources based on an observation decomposition framework, and constructing an independent sub-grid for each decomposition source and each receiving point in each time channel; the decomposition of the emission source is carried out in an iteration mode, in each time channel, the size of the current decomposition source is jointly determined by the current transceiving distance and the size and transceiving distance of the decomposition source of the last decomposition, the transceiving distance required by the next decomposition is generated, and recursion is carried out until the decomposition is completed. Sub-models are obtained according to the sub-grids, the local magnetic vector potential of each sub-model at the initial moment is calculated through the Biot-Savart law, a double-rotation control equation of the sub-models about the magnetic induction intensity is solved, magnetic field response results of the sub-models are obtained, the magnetic field response results of all the sub-models are synthesized, and magnetic induction intensity distribution of the global model is obtained. The method has the advantages of being high in calculation speed and low in memory requirement.

The invention relates to the technical field of electromagnetic field analysis and unmanned aerial vehicle inspection, in particular to a power transmission line unmanned aerial vehicle inspection safety distance electromagnetic field analysis method and system, and the method comprises the steps: building an electromagnetic field model of a power transmission line through a Maxwell equation set, and representing an electromagnetic field as a discretized finite element equation set; performing approximate processing on node potential and magnetic vector potential through energy functional of the electric field and the magnetic field in combination with a shape function, and solving electric field distribution and magnetic field intensity at the node; and in combination with simulation calculation, simulating the equivalent radius and charge distribution characteristics of a power transmission line conductor, and calculating the minimum safe flight distance of the unmanned aerial vehicle in the inspection task. The method has the advantages that accurate modeling and simulation analysis are conducted on the electromagnetic field of the power transmission line through the finite element method, and the safety and efficiency of unmanned aerial vehicle inspection operation are remarkably improved.

The application provides a ground-air frequency domain electromagnetic full-area apparent resistivity imaging method based on sensitivity, which comprises uniform half-space discretization, calculation of underground electric field response value based on magnetic vector potential function, calculation of air magnetic field response based on tensor Green function, calculation of coupling sensitivity based on air vertical magnetic field response, calculation of full-area apparent resistivity based on quasi-static approximation formula of vertical magnetic induction intensity of uniform ground space, and calculation of full-area apparent resistivity combined with each system parameter. The application solves the problem of volume effect influence on the existing ground-air frequency domain data interpretation effect, and through the calculation of the coupling sensitivity of the underground grid, the calculation of the full-area apparent resistivity based on the coupling sensitivity can be realized, the coupling relationship between the measured magnetic field at the receiving point and the underground grid is considered, the volume effect is corrected, the apparent resistivity imaging precision is improved, and then the ground-air frequency domain data interpretation effect is improved.

The invention discloses a three-dimensional eddy current field identification method and system for a converter transformer. The method comprises the following steps: acquiring target structure working condition parameters of a to-be-identified converter transformer; obtaining target magnetic vector potential distribution low-dimensional features corresponding to the target structure working condition parameters according to a preset reduced-order mapping model; wherein the reduced-order mapping model is used for representing a mapping relation between structure working condition parameters and magnetic vector potential distribution low-dimensional features; performing three-dimensional eddy current field identification on the target magnetic vector potential distribution low-dimensional features by using a pre-trained three-dimensional eddy current field identification network to obtain three-dimensional eddy current field distribution information of the to-be-identified converter transformer; wherein the three-dimensional eddy current field identification network is obtained by training a DGM network by using three-dimensional eddy current field finite element simulation data of the converter transformer under different structure working condition parameters. According to the method, the three-dimensional eddy current field identification efficiency of the converter transformer can be remarkably improved.

The invention discloses a non-ferromagnetic abrasive particle motion effect and time-harmonic field coupled transient electromagnetic field analysis method, and relates to the technical field of three-coil electromagnetic abrasive particle sensor simulation. In order to solve the defect that induced voltage generated by moving abrasive particles cannot be accurately analyzed in the prior art, the technical scheme provided by the invention comprises the following steps: collecting an incident magnetic field vector generated by an excitation coil in a spherical conductor area; eddy current distribution generated by the non-ferromagnetic abrasive particles under the independent action of the exciting coil 1 and the exciting coil 2 is obtained; establishing a magnetic vector potential control equation and performing Fourier transform to obtain a general solution; solving space magnetic vector potential change; calculating equivalent voltage in the induction coil; and integration is carried out on the equivalent excitation source in the non-ferromagnetic abrasive particles, and induced voltage generated when the non-ferromagnetic abrasive particles pass through the sensor is obtained. The method is suitable for high-precision modeling and simulation analysis work of the dynamic induced voltage of the abrasive particles in a non-ferromagnetic abrasive particle online monitoring system.

The application discloses a kind of three-dimensional electromagnetic potential forward modeling self-adapting finite element method, comprising the following steps: S1, using Coulomb specification to convert Maxwell equation group into the control equation of scalar potential and vector potential;S2, the gradient term of the control equation in introducing Lagrange multiplier, the solving region is discretized, and linear equation set of finite element is constructed;S3, the linear equation set of finite element is solved;S4, using the error generated by current density discontinuity as posteriori error estimator, dual weighted posteriori error estimator is added, and target grid needing refinement is determined;S5, using eight sub-refinement strategy to encrypt the target grid;S6, using the grid after encryption carries out finite element forward modeling calculation.The application can enhance the stability in the solving process of finite element system equation, and also can improve the calculation efficiency by reducing the calculation amount of additional system equation caused by grid self-adapting.

The invention provides an electromagnetic field rapid prediction method and system for a levitation electromagnet of a maglev train, and aims to solve the problems of coil strong source, iron core nonlinear constitutive and local high-gradient multi-scale coupling of the levitation electromagnet under typical working conditions, a coil area is extracted based on electromagnetic field sample data, and a distance field is constructed. And according to the structural characteristics of the suspension electromagnet and the distance field, an electromagnet solving area is divided into a coil conductor sub-domain and a plurality of iron core sub-domains with different distance levels, and sub-networks are constructed respectively. In the training process, Maxwell quasi-static equation residual errors and material constitutive consistency constraints are introduced into the sub-domains, and magnetic vector potential continuity and magnetic induction intensity normal continuity constraints are applied to sub-domain interfaces; and a time-varying hybrid scheduling mechanism of a right-end source item of an iron core domain is further introduced, so that the prediction stability and precision of a strong source region and a high-gradient region are improved. In the reasoning stage, electromagnetic field distribution can be rapidly output, and support is provided for rapid calculation of electromagnetic force, eddy-current loss and the like.

The invention provides an underground delivery pipe three-dimensional finite element forward modeling method and system based on frequency domain electromagnetism, and the method comprises the steps: building an underground delivery pipe three-dimensional model, and carrying out the hybrid mesh generation of the underground delivery pipe three-dimensional model; introducing a time harmonic factor, constructing a frequency domain Maxwell equation set, and based on the subdivided underground delivery pipe three-dimensional model, combining the magnetic vector potential of each unit to establish a unit matrix; based on the unit matrix, assembling a linear equation set; an observation area is divided into a plurality of sub-areas, an emission source is arranged in each sub-area, an assembled linear equation set is solved for the three-dimensional models of the sub-areas with different frequencies in a parallel mode, and three-dimensional rapid forward modeling of the underground conveying pipe is achieved. According to the method, the observation area is divided into a plurality of sub-areas, and the three-dimensional model of each sub-area under different frequencies is calculated by using the parallel algorithm, so that the three-dimensional rapid forward modeling of the underground delivery pipe is realized, and the calculation efficiency of the three-dimensional forward modeling is improved.

The invention relates to a transient electromagnetic field-circuit coupling high-precision calculation method based on an A-alpha formula, and the method comprises the steps: dividing grid data into a plurality of polyhedral smooth regions with corresponding edges as centers according to the edges in the grid data of a three-dimensional motor 1 / 8 periodic model; a smooth vector shape function of edges and a smooth shape function of nodes in the polyhedron smooth domain are calculated; constructing a transient field-circuit coupling equation set based on an A-alpha formula, transient eddy current and coulomb specifications, and rewriting the transient field-circuit coupling equation set according to the smooth vector shape function of each edge, the smooth shape function of each node and a Galerkin method to obtain a transient field-circuit coupling system equation; further rewriting the transient field-circuit coupled system equation into a Newton iteration linear equation; and iteratively solving the Newton iteration linear equation by adopting a Newton iteration method until the Newton iteration linear equation converges to obtain a magnetic vector bit in field-circuit coupling, thereby realizing high-precision numerical solution of the transient field-circuit coupling problem in the complex motor system.