19 results about "Maxwell's equations" patented technology

The invention discloses a three-dimensional electromagnetic inverse scattering imaging method of a diffusion model based on physical constraint embedding. The method comprises the following steps: 1, in a specific three-dimensional electromagnetic inverse scattering imaging environment, defining a dielectric constant of an imaging area, arranging a transmitting and receiving antenna array at the periphery, and obtaining scattering field data of a target area for constructing an input and output sample pair of a diffusion model; 2, constructing a diffusion model on the three-dimensional grid space; 3, introducing a physical consistency constraint term based on a Maxwell equation set in the training stage of the diffusion model; and 4, synthesizing the generation loss and the physical constraint loss of the diffusion model, constructing a joint optimization objective function, and carrying out iterative updating on network parameters by adopting an end-to-end back propagation algorithm until the model converges. According to the method, the spatial resolution and continuity of three-dimensional imaging are remarkably improved, the stability and robustness of inverse scattering reconstruction are improved, and the physical consistency is enhanced. And high-precision and interpretable three-dimensional electromagnetic inverse scattering imaging can be realized.

The application belongs to the field of transformers, and discloses a linear phase-shifting transformer equivalent circuit modeling and performance parameter obtaining method, analyzes the electromagnetic relationship between the primary side winding and the air gap when the linear phase-shifting transformer is in steady-state operation, and Maxwell equations of the linear phase-shifting transformer; based on the theory of one-dimensional field, the equivalent circuit of the linear phase-shifting transformer is established and solved when the longitudinal edge effect is considered. The performance parameter obtaining method is also disclosed, which comprises: solving the established equivalent circuit model to obtain the resistance and leakage reactance of the primary side winding, the excitation reactance, and the secondary side winding resistance; and calculating the performance parameters of the linear phase-shifting transformer based on the equivalent circuit solving result. The application considers the actual situation of the transformer in electromagnetic analysis, the model is more accurate, the calculation precision is high, the winding loss, efficiency and voltage regulation rate and other performance parameters of the transformer can be quickly and effectively calculated, the application is relatively convenient in actual calculation and analysis, and has high practical value.

This invention discloses a method for predicting electromagnetic radiation from cables. First, a one-dimensional conductor model of the target cable is established in a three-dimensional simulation space, and its axial direction is divided into multiple segments. Current data for each segment is solved using the finite-difference time-domain method. Then, the three-dimensional simulation space is discretized using a Yee grid, and virtual observation points corresponding to actual observation points are determined. Standard electric field and standard magnetic field update equations are established on the Yee grid based on Maxwell's equations. A field-circuit co-simulation process is established, and in each time step iteration, the current data is equivalently coupled to the standard electric field and standard magnetic field update equations to achieve synchronous updates of transmission line current and spatial electromagnetic field. Finally, this process is executed until a preset termination condition is met, and the time-domain electromagnetic field response at the virtual observation points is extracted as the time-domain electromagnetic radiation prediction result. The advantages are high prediction accuracy and high prediction efficiency.

This invention proposes a method and system for simulating the vibrational displacement distribution of magnetic particles based on multiphysics coupling, comprising: Step S1: constructing a three-dimensional geometric model containing biological tissue and magnetic particles; Step S2: setting material parameters for each region; Step S3: configuring multiphysics; Step S4: performing mesh generation; Step S5: setting solver parameters; Step S6: using the finite element method to solve the force of the magnetic field on the magnetic particles in Maxwell's equations and describing the magnetic field distribution in the magnetic particle region; Step S7: using the magnetic force obtained in Step S6 as a load, inputting it into the solid mechanics field module, and solving the vibrational displacement distribution in the magnetic particle region based on the wave equation. Furthermore, the system of this invention includes: a three-dimensional geometric model group, a material library, a mesh module, and a multiphysics module. This invention accurately simulates the vibrational displacement distribution of magnetic particles within biological tissue under the action of an alternating magnetic field, revealing the coupling law between magnetic fields and solid mechanics.

The invention relates to the technical field of ocean geophysical exploration, and provides an island tail flow induced electromagnetic field simulation method based on magnetohydrodynamics. The method comprises the following steps: constructing a three-dimensional island wake flow fluid dynamic model; coupling an equation for describing seawater motion with a Maxwell equation set for describing electromagnetic field evolution, and constructing a magnetohydrodynamic control equation set; modeling the turbulence effect of seawater movement; the magnetohydrodynamics control equation set is solved, the ocean current velocity field and the induced electromagnetic field intensity are obtained, and the induced electromagnetic field intensity comprises the induced electric field intensity and the induced magnetic field intensity. The three-dimensional island wake flow hydrodynamic model constructed by the method comprehensively considers the seawater vertical layering flow velocity profile and background geomagnetic field parameters, and the constructed magnetohydrodynamic control equation set fully considers the seawater motion, so that the model can truly reflect a terrain-flow field-electromagnetic field multi-scale coupling mechanism.

The invention discloses an electromagnetic simulation method of a microstrip line and electronic equipment. According to the microstrip line electromagnetic simulation method provided by the invention, the frequency domain polarization model is constructed by decomposing a complex dispersive medium model into superposition of a plurality of Debye relaxation terms, and the frequency domain response of each unit is converted into an independent time domain update relationship by using an auxiliary differential equation method; therefore, the high calculation overhead caused by the traditional time domain convolution operation is thoroughly avoided; furthermore, the updating relations and Maxwell equations are coupled to construct a joint solving model, discretization is carried out through a time domain finite difference method, an explicit field quantity updating operator is generated, and the electric field, the magnetic field and the polarization current component can be efficiently and synchronously updated in time domain iterative calculation. According to the method, high-precision modeling of the broadband dispersion characteristic of the PCB microstrip line is ensured, and meanwhile, the simulation calculation efficiency is remarkably improved.

The invention discloses a power transmission cable sheath insulation on-line state monitoring method, mainly relates to the technical field of on-line state monitoring, and aims to solve the problems that single-parameter monitoring is difficult to reflect a multi-field coupling mechanism of insulation degradation, infrared temperature measurement is influenced by environmental radiation and surface emissivity, off-line detection needs power-off operation, and the detection efficiency is low in the prior art. And response lag is solved. Comprising the following steps: taking a graph structure state flow as input, driving a physical simulation engine based on electromagnetic-thermal-current three-field coupling, and simulating a transient charge migration path of a partial discharge pulse in an XLPE sheath; generating a transient electromagnetic fingerprint corresponding to each node by solving and correcting a Maxwell equation set; and inputting the insulation degradation electromagnetic fingerprints into a multi-agent game model based on information entropy flow, regarding each cable node as an agent with state evaluation capability, and outputting a dynamic decision signal of an insulation health state.

The application discloses a calculation method and system for the transmission and scattering process of low-frequency electromagnetic waves in the brain, and relates to the technical field of brain detection. The method simplifies the brain tissue into a homogeneous isotropic spherical model, which significantly reduces the calculation complexity and lays a foundation for efficient solution. Then, an electromagnetic wave propagation and scattering physical model based on Maxwell's equations is constructed to accurately describe the motion law of electromagnetic waves in brain tissue. The physical model is deeply integrated into a deep learning algorithm to efficiently solve the three-dimensional electromagnetic field distribution in the brain. Finally, the propagation path, energy distribution and scattering field characteristics of electromagnetic waves are analyzed to realize the positioning and qualitative diagnosis of brain edema, tumors and other lesions, and provide key support for brain tissue health assessment. The application overcomes the efficiency bottleneck of traditional numerical methods in brain electromagnetic calculation, improves the timeliness and accuracy of brain disease diagnosis, and provides reliable technical support for bedside rapid diagnosis of acute conditions such as stroke.

The application provides a full current wave impedance apparent resistivity detection method and system, and belongs to the technical field of survey geophysics. The method realizes apparent resistivity detection of a target area by using a radio frequency magnetotelluric method (RMT). The method mainly comprises the following steps: collecting detection data, using a sensor with a frequency range covering 1 MHz to obtain orthogonal electric field components and magnetic field components at measuring points in a detection area; obtaining dielectric constants and magnetic permeabilities of a shallow surface layer; and using the detection data to calculate full current wave impedance apparent resistivities at the measuring points by using a full current wave impedance apparent resistivity model which is not limited by quasi-static conditions. In the application, the full current wave impedance apparent resistivity model considering displacement current is derived from Maxwell equations, so that the model is not limited by quasi-static conditions and will not cause distortion of apparent resistivity at high frequencies due to non-compliance with quasi-static assumptions. The model can measure both artificial source excited electromagnetic fields and natural electromagnetic fields.

The application relates to the technical field of metallurgical continuous casting, and discloses a numerical calculation method for defining a continuous casting electromagnetic stirring area. Firstly, based on the parameters of a continuous casting machine and the cross-sectional size of a casting blank, a three-dimensional transient solidification simulation system coupling flow, heat transfer, mass transfer and a solidification model is constructed; then Maxwell equations are embedded into the system in the form of a source term through a user-defined function, bidirectional coupling calculation of an alternating magnetic field and multiple physical fields is realized, and multiple physical field distribution results are synchronously obtained; subsequently, a solidification rate dynamic calculation model is established based on a temperature field, a target stirring area is determined; finally, combined with real-time process parameters, optimal position coordinates of electromagnetic stirring are dynamically calculated through a spatial vector algorithm, the stirring shaft angle and the action range are synchronously corrected based on the solidification front morphology, and the position, direction and action range of electromagnetic stirring are cooperatively optimized and controlled. The application solves the problem that the fixed electromagnetic stirring does not match the dynamic solidification process, and can effectively improve the core quality of the casting blank.

The application belongs to the technical field of wave propagation, and particularly discloses a numerical simulation method for propagation characteristics before and after high-power microwave atmospheric breakdown, which is based on a rotational body time-domain finite difference method to solve an electron fluid model improved based on an empirical formula, the electron fluid model including a Maxwell equation set, an electron density continuity equation, an electron fluid momentum conservation equation and an electron fluid energy equation, and the evolution processes of electromagnetic fields, electron densities and electron energies before and after high-power microwave atmospheric breakdown can be calculated by solving the improved electron fluid model. According to different atmospheric pressures and initial electron densities, the application adopts more accurate transport coefficients, so that the simulation precision can be greatly improved; and the application can also convert a three-dimensional electromagnetic propagation problem into a quasi-two-dimensional problem, so that the simulation time can be greatly shortened and the computer memory can be saved.

A multi-winding high-frequency transformer leakage inductance analytical calculation method, comprising: determining the number of leakage inductances of the secondary winding corresponding to different primary windings according to the number of primary and secondary windings of the multi-winding high-frequency transformer; dividing the leakage magnetic energy region corresponding to different leakage inductances into winding interlayer insulation region, winding insulation region, through-flow winding region and open-circuit winding region; deriving the magnetic field intensity of the winding interlayer insulation region and the winding insulation region; deriving the magnetic field intensity of the through-flow winding region and the open-circuit winding region based on Maxwell's equations; further integrating the corresponding leakage magnetic energy according to the magnetic field intensity of each region; calculating the leakage magnetic energy corresponding to each leakage inductance according to the different leakage magnetic energy calculation region of each leakage inductance, summing the leakage magnetic energy of the corresponding region, and then calculating the leakage inductance parameters according to the magnetic field energy method. The method considers the open-circuit winding unique in the leakage inductance calculation process of the multi-winding high-frequency transformer, and accurately calculates the leakage magnetic energy of the open-circuit winding.

The invention discloses a ground penetrating radar (GPR) inversion method based on time-frequency joint physical constraint, and relates to the technical field of ground penetrating radar detection. The method comprises the following steps: firstly, acquiring GPR common offset B-scan echo data, and constructing a data set through anti-noise processing and forward simulation; decomposing data through two-dimensional discrete wavelet transform, and outputting a fusion feature map through a time-frequency joint feature fusion module; introducing a Maxwell equation set, an electromagnetic wave propagation equation and an electromagnetic field boundary equation to construct multiple constraints; and finally, outputting a relative dielectric constant distribution diagram, and carrying out visualization and precision verification on the relative dielectric constant distribution diagram for detection. According to the method, the noise immunity and the small target recognition precision are improved through time-frequency deep fusion, the result reasonability is guaranteed through physical constraints, the efficiency is optimized based on the DLFUNet network, the method is suitable for underground pipe network distinguishing, roadbed disease diagnosis and other scenes, and the problems that a traditional method is insufficient in precision and poor in physical interpretability under the low signal-to-noise ratio are solved.

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 application discloses an electromagnetic characteristic analysis method and device of a target object, an electronic device and a computer readable storage medium. The method comprises the following steps: performing simulation modeling according to boundary condition information of the target object to obtain a simulation model of the target object; performing grid division on the simulation model by using a preset structure, and establishing a time-varying electromagnetic field of a Maxwell equation group based on the simulation model after the grid division; implicitly solving the time-varying electromagnetic field of the Maxwell equation group based on double iteration of physical time and virtual time; and outputting an electromagnetic characteristic analysis result of the target object when the time-varying electromagnetic field of the Maxwell equation group converges. The electromagnetic characteristic analysis method provided by the application improves the electromagnetic characteristic analysis efficiency of the target object.

This invention discloses a method and system for electromagnetic and thermal conformal multiphysics simulation of airborne radomes under lightning strike conditions. By employing conformal techniques—applying edge area weighting to the electromagnetic field and volume weighting to the temperature field—high-precision discretization of Maxwell's equations and the heat conduction equations is achieved within a finite-difference time-domain framework, effectively resolving modeling errors caused by the stepped approximation of the curved surface structure of the airborne radome. Furthermore, by interpolating the edge electric field to the mesh center to construct a physically consistent Joule heat source and establishing a bidirectional coupling iterative mechanism between the electromagnetic and temperature fields, co-simulation of electromagnetic and Joule thermal effects under strong electromagnetic pulse lightning strikes is achieved. This method significantly improves computational accuracy and efficiency without requiring excessive mesh refinement, accurately predicting the degradation of electromagnetic transmission performance and structural damage characteristics of the radome after a lightning strike, providing reliable simulation support for lightning-resistant design and performance evaluation.

The application discloses a modeling method of low-frequency electromagnetic noise induced by underwater platform motion, and establishes an underwater platform motion posture equation under the influence of sea waves based on a Maxwell equation set, and analyzes the change of a velocity field of the underwater platform to realize modeling of low-frequency electromagnetic field noise induced by underwater platform motion, and then obtains amplitude distribution and spectrum characteristics of the low-frequency electromagnetic noise through simulation. The application provides a model and a method for analyzing and suppressing noise when low-frequency electromagnetic signals of an underwater target are used for detection and positioning.

The invention discloses a planar multi-pole magnetic field decomposition method based on a genetic algorithm. Quantitative decomposition of multi-pole components of a magnetic field is realized by fitting constant coefficients in a two-dimensional complex magnetic potential expression in a Maxwell equation set. The method comprises the following steps: preprocessing a two-dimensional plane complex magnetic potential obtained by actual measurement / simulation to obtain an initial population of a genetic algorithm, selecting a proper population scale, crossover and mutation probabilities and a termination evolution algebra, constructing a fitness function based on an optimization target, and carrying out iterative calculation to obtain a global better decomposition result of a multipole magnetic field. And on the basis, least square method optimization is further carried out, and finally, a globally optimal multipole magnetic field decomposition result is obtained.

The application discloses a power cable sheath insulation online state monitoring method, and mainly relates to the technical field of online state monitoring, and aims to solve the problems that the single parameter monitoring of the existing scheme is difficult to reflect the multi-field coupling mechanism of insulation deterioration, the infrared temperature measurement is affected by environmental radiation and surface emissivity, offline detection needs power-off operation, and response lag exists. The method comprises the following steps: taking a graph structure state flow as input, driving a physical simulation engine based on electromagnetic-thermal-current three-field coupling, simulating the transient charge migration path of partial discharge pulses in the XLPE sheath; solving the modified Maxwell equation set to generate the transient electromagnetic fingerprint corresponding to each node; inputting the insulation deterioration electromagnetic fingerprint into a multi-agent game model based on information entropy flow, regarding each cable node as an agent with state evaluation capability, and outputting a dynamic decision signal of the insulation health state.