83 results about "Electromagnetic model" patented technology

A system and method for obtaining information about the spatial distribution of photoreceptor activity and neural activity in the retina using simultaneously recorded multiple biopotential signals. The information thus gathered is used to assess retinal dysfunction due to trauma or disease. The biopotential signals are recorded from the surface of the eye and head using a plurality of electrodes, including those integral to a contact lens. The biopotential signals are recorded before, during and after the presentation of an optical stimulus to the subject eye. The recorded biopotential signals are then analyzed and interpreted to reveal the distribution of photoreceptor activity and neural activity across the retina. The analysis and interpretation of the biopotential signals is quantitative, and makes use of an electromagnetic model of the subject eye. The subject may be animal or human.

The invention provides a reversely deducing prediction method of electromagnetic coupling between large array antennae of a ship. According to an electromagnetic coupling theory of a transmitting array antenna to array elements of a receiving array antenna, a full-wave electromagnetic model is built for a transmitting array antenna model machine and a receiving array element antenna, and premixing simulation solving is carried out on a coupling field of the transmitting array antenna model machine by adopting a consistency diffraction theory and a vector overlaying method on the basis of an amplitude-phase combination theory; an electromagnetic coupling test on a local array antenna is carried out in an open area test site, result of the electromagnetic coupling test on the local array antenna is compared and verified with a network parameter model, and a quantizing factor under an actual condition is used for correcting an interference field propagation model to ensure that simulation calculation is matched with the test result. The method provided by the invention gives play to the accuracy advantage of a full-wave numerical method, and provides an interface for simulation test correction, and the problem of overdesign or underdesign caused by the simulation calculation carried out under an ideal state is solved by reversely deducing.

The invention relates to a human body communication channel modeling method based on a non-uniform medium and a system thereof. The method comprises the following steps that a human body is divided into multiple structural models according to the structure; the multiple structural models are abstracted into regular geometries; medium layer division is performed in the internal parts of all the structural models, thickness of all medium layers is arranged, and equivalent electrical parameters of all the structural models are computed; and the uniform medium structural models with different electrical parameters are recombined and a human body contour is recovered so that multiple non-uniform medium human body electromagnetic models of the uniform medium structural models with different electrical parameters are constructed. According to the aforementioned human body communication channel modeling method based on the non-uniform medium and the system thereof, the non-uniform medium human body electromagnetic models of the uniform medium structural models with different electrical parameters are constructed so that accuracy is high in comparison with unified uniform medium human body models. Besides, all the structural models are equivalent to the uniform medium structural models so that subsequent computation is simplified and computation space is saved.

The invention belongs to the technical field of power transmission and power distribution, and particularly relates to a negative sequence component-considering MMC system simplified electromagnetic transient state modeling method. The modeling method comprises the steps of determining an analytical expression of a negative sequence component-considering MMC converter station internal sub module capacitive voltage and a bridge arm current in an abc static coordinate system according to internal dynamic characteristics of the MMC; establishing a simplified electromagnetic transient state model of the negative sequence component-considering MMC converter station and an alternating current and direct current system thereof in a dq rotary coordinate system according to an average switching function model; according to actual control strategies, establishing a control system simplified electromagnetic transient state model considering a phase sequence separation link and positive sequence and negative sequence current vector controllers; and establishing a negative sequence separation-considering MMC system simplified electromagnetic model according to the simplified electromagnetic transient state model of the converter station and the alternating current and direct current system thereof and the control system simplified electromagnetic transient state model, wherein the dynamic process, system parameter design and stability analysis of the negative sequence component and negative sequence control in the MMC converter station can be researched conveniently.

The invention discloses a method and a system for testing the receiving sensitivity of mobile terminals. The method includes the steps that a geometric testing model of the component to be tested which is composed of the mobile terminal and the human head electromagnetic model is constructed, and the component to be tested is put on the three-dimensional test rotating table; the component to be tested and the simulator are put into the testing environment screened from external wireless; the mobile terminal and the simulator are kept in a normal working state to wirelessly transmit and receive; the parameter of receiving sensitivity are tested and processed to obtained. The method and the system for testing the receiving sensitivity of mobile terminals in the invention has the advantages of low environmental requirement, easy testing, and easy operation and so on.

The invention discloses a feed source position compensation method of a large-scale deformed single reflection surface antenna, which mainly solves the problem that the electric performance of a single reflection surface antenna is lowered due to thermal deformation. The method adopts the scheme of 1, establishing a finite element model of an undeformed single reflection surface antenna according to the structure parameter of the antenna; 2, calculating node coordinates when deformation occurs after a temperature load is loaded on the undeformed single reflection surface antenna; 3, extracting the node coordinates and unit information of a deformed main reflection surface, and establishing an electromagnetic model of the thermal deformed main reflection surface of the antenna; 4, calculating the electric performance before the antenna is compensated in the electromagnetic model of the thermal deformed main reflection surface of the antenna; 5, optimizing deformation parameters of the deformed main reflection surface by means of a genetic algorithm, obtaining the position and the direction of a feed source from the deformation parameters, and calculating the electric performance after the antenna is compensated; 6, comparing the electric performance of the antenna before and after compensation to judge whether the improvement of the electric performance meets the requirement, if so, judging the position to be the optimum position of the feed source, and if not, setting and optimizing the parameters again and calculating until the requirement is met.

The invention belongs to the field of numerical simulation technology of ECR ion sources, and particularly relates to an MPM hybrid algorithm applied to numerical simulation of an ECR ion source. Thealgorithm is suitable for use in an ECR ion source structure. The MPM hybrid algorithm of simulation of the ECR ion source is established through combining an MAGY theory and PIC/MCC simulation algorithms, a time-varying electromagnetic field is described by the MAGY theory, self-consistent interaction of charged particles and the electromagnetic field is described by the PIC algorithm, and inter-particle collision processes are described by the MCC algorithm. A complex and complete solving process which originally needs to be carried out on Maxwell's equations is enabled to be simplified to solving on a set of coupled one-dimensional partial differential equations about mode amplitudes, relatively larger time step length can also be taken due to that compared with high-frequency cycles, changes of the mode amplitudes are slower, and computational complexity and a computational amount are greatly reduced. In addition, an electromagnetic model is adopted, and thus compared with adoptingan electrostatic model, the algorithm can more accurately describe an actual physical process.

The invention provides an aircraft electromagnetic environment effect simulation method, which comprises the steps of importing an aircraft CAD model, and performing mold repairing and multi-scale subdivision on the aircraft CAD model to form an aircraft grid model; setting airplane material electromagnetic parameters by utilizing the airplane composite material electromagnetic parameter library;performing regional decomposition numerical simulation modeling on the aircraft grid model in combination with material electromagnetic parameters to obtain an aircraft electromagnetic model; and in combination with a preset electromagnetic excitation source, calculating an electromagnetic field intensity value of the internal area of the aircraft by adopting an adaptive cross approximation algorithm ACI or a multilayer fast multipole algorithm MLFMA on the basis of a moment method MoM for the aircraft electromagnetic model; setting a cable harness path and electrical characteristic information, and establishing a harness electromagnetic model in the aircraft electromagnetic model by utilizing the aircraft harness modeling model library; and in combination with the electromagnetic field intensity value, adopting a high-frequency field line coupling analysis algorithm for the wire harness electromagnetic model to calculate an induced current value on an aircraft cable harness.

The invention discloses a scaling target construction method containing a gap scattering inhibition coating. The method comprises the following steps: on the basis of considering the reflection characteristic of a scaling material, carrying out simulation analysis on the structural effect between a target weak scattering source and the material, and then optimizing a scaling target model with closer scattering characteristics by adjusting the slit width; T. The construction method further comprises the steps of S1, inputting prototype stealth material data and parameters of the seam-containingmodel; S; s2, calculating the oblique reflectivity of the prototype stealth material; S; s3, constructing a scaling material; S; s4, setting the width of the gap; S; s5, performing RCS simulation comparison; and S6, outputting the scaling target model. The method is used for an electromagnetic model containing a coating and weak scattering, and the consistency of reflection and scattering characteristics of a scaling model can be ensured. The scale model constructed by the invention is used for carrying out slot width compensation on the weak scattering source, and is more convenient for manufacturing the scale model.

The invention discloses a method for evaluating the influence of an offshore wind plant on the detection efficiency of ground wave beyond visual range radar. The method comprises the following steps:according to ground wave over-the-horizon radar parameters and a pre-selected area of a wind power plant, carrying out scene analysis, and screening out objects needing key analysis; establishing a fan electromagnetic model according to the provided parameters of a wind turbine generator, and realizing establishment of a single fan electromagnetic model; according to longitude and latitude coordinates of a fan of a pre-built wind power plant and radar relative position information, building an array in FEKO electromagnetic calculation software, building a scene model, and analyzing shielding influences; calculating RCS changes of a single fan device in different states; analyzing the influence of Doppler frequency; deriving a multipath effect theoretical formula; enabling scene actual measurement to be equivalent to electromagnetic environment noise data, and evaluating the influence range of the wind power plant. By means of electromagnetic simulation calculation, theoretical derivation, actual measurement scene equivalence and the like, a quantitative evaluation result is given.

The invention discloses a method and system for establishing an electromagnetic model of a circuit breaker arc combustion process. The method comprises the following steps: acquiring the structural parameters of a circuit breaker, establishing a circuit breaker simulation model based on a preset proportion according to the structural parameters of the circuit breaker, wherein the structural parameters of the circuit breaker include the structure, the shape and size, and the material properties of the circuit breaker; acquiring the electromagnetic environment parameters of the circuit breaker, and establishing a simulating electromagnetic environment where the circuit breaker simulation model is located in the arc combustion process according to the electromagnetic environment parameters; simulating a high-frequency discharging excitation source by using a Gaussian pulse signal in order to perform simulating discharging on the circuit breaker simulation model in the simulating electromagnetic environment to simulate the circuit breaker arc combustion process; and detecting the change of an electromagnetic wave signal at preset distance to the circuit breaker simulation model in the simulated circuit breaker arc combustion process. The method and system can accurately reflect the arc combustion process of the circuit breaker and can further determine the ablation degree of the circuit breaker according to the arc combustion process.

The invention discloses a full-electromagnetic transient modeling method for a power grid, relates to a power grid full-electromagnetic transient modeling technology, and aims to solve the problem of poor calculation precision when an existing power grid electromechanical transient model is used for performing fault-free electromagnetic transient calculation on an alternating-current and direct-current interconnected power grid. The method comprises the steps of by means of an all-digital real-time simulation system of a power system, checking electromechanical model parameters in a PSASP platform according to an electromechanical data checking and correcting method; establishing a power grid alternating current electromechanical model by using the checked electromechanical model parameters; converting the established alternating-current electromechanical model of the power grid into a backbone grid electromagnetic model; establishing a power grid direct-current electromechanical model by using the checked electromechanical model parameters; initializing the direct-current electromechanical model of the power grid; and adding the initialized power grid direct-current electromechanical model into the backbone grid electromagnetic model to generate a power grid full-electromagnetic transient model. The beneficial effect is that the calculation precision is high.

The invention relates to a filter-based electromagnetic transient state simulation method and system. The method comprises, through a group of simulative filter circuits, simulating a plurality of groups of LCC (leadless chip carrier) converter station alternate current filters of the same kind to the simulative filter circuits, and through a parameter setting method, simulating the switch operation of the LCC converter station alternate current filters, wherein the parameter setting method is a method in which the electromagnetic transient state equivalent computing circuit of the filter circuits in real time corrects a historical current source. By compressing a dozen of alternate current filters of a practical LCC converter station into a plurality of types for simulation in an electromagnetic transient state program, the filter-based electromagnetic transient state simulation method and system can greatly reduce the number of electrical nodes and elements of a direct current powertransmission electromagnetic model, accelerate simulative models, and meanwhile have no loss in the filtering effects of the filters or the simulation precision of dynamic switching processes, therebyhaving high practical promotion values.

The invention provides an electromagnetic optimization method and device for a high-temperature superconductive annular energy-storage magnet. The method comprises the steps that initial structural parameters are generated; an electromagnetic model of the high-temperature superconductive annular energy-storage magnet is established according to the initial structural parameters; electromagnetic parameters are determined according to the electromagnetic model of the high-temperature superconductive annular energy-storage magnet; and energy storage capacity of the high-temperature superconductive annular energy-storage magnet is calculated, and electromagnetic optimization is performed on the high-temperature superconductive annular energy-storage magnet with maximum energy storage capacityof the high-temperature superconductive annular energy-storage magnet being a goal. Through the electromagnetic optimization method and device, under the condition that total wire consumption is certain, electromagnetic optimization of the high-temperature superconductive annular energy-storage magnet with the maximum energy storage capacity under different operating temperatures is realized, andcomplementation of advantages is formed; Maxwell's equations and a finite element method are utilized to establish the electromagnetic model of the high-temperature superconductive annular energy-storage magnet, magnetic induction intensity distribution and a leakage magnetic field of the high-temperature superconductive annular energy-storage magnet can be analyzed, inductance and the energy storage capacity can be calculated, calculation performance is efficient, and the calculation result is precise.

The invention relates to a hybrid simulation-based electromagnetic direct-current model automatic adjustment method and system. The method comprises the steps of obtaining initial running condition information from electromagnetic side power flow data, and assigning initial values to initialized information components of a pre-built electromagnetic direct-current model; based on control process parameters of the information components in the initial running condition information, adjusting a current running state of the electromagnetic direct-current model; and when current running state dataafter adjustment is consistent with the electromagnetic side power flow data, switching off a clamping power supply on a converter bus, thereby enabling the electromagnetic direct-current model and anelectromechanical side power grid to form a closed loop through a hybrid simulation interface, and starting hybrid simulation. Therefore, quick and automatic adjustment of running conditions of the electromagnetic side direct-current power transmission model in electromechanical-electromagnetic hybrid simulation of a large-scale alternating-current and direct-current power grid is realized; the workload of manual adjustment of running modes of the electromagnetic direct-current model during the hybrid simulation of the alternating-current and direct-current power grid is greatly reduced; quick adjustment of the running modes of the direct-current electromagnetic model is realized; and the simulation efficiency is remarkably improved.

The invention provides a method of acquiring channel information for ray tracing of anti- or scattered propagation, and the method comprises the following steps of implementing geometric description of each object in three layers, wherein the first layer is a bounding box layer, the second layer is a closed polygon layer, and the third layer is a triangular panel layer; performing spatial segmentation, occlusion detection and visible surface decision processing on the object based on the geometric description implemented by the three layers of each object; obtaining the reflection and scattering paths of the ray based on the results of the spatial segmentation, occlusion detection and visible surface decision processing of each object, and obtaining the electromagnetic information of the effective reflection diameter and the scattering diameter of the ray based on the reflection and scattering paths of the ray and combined with the electromagnetic model. The method provided by the invention describes planes of different types by hierarchical geometric description of the tracked objects, and flexibly supports the three-dimensional description of the complex structures and the regular objects, thereby making the ray tracing adapt to various types of scenes, broadening the application range, and increasing the anti- or scattered multipath geometry calculation efficiency.

The invention relates to an optimum design method for a flux leakage problem of an alternating-current generator for a car. The optimum design method comprises the steps that the basic parameter of a finite element model is set, and the basic structure parameter of the alternating-current generator is set; no-load electromagnetic models of a rotor, a stator, a stator winding and a field winding of the alternating-current generator are set, and a transient electromagnetic field of a motor is solved through a three-dimensional finite element method; boundary adding is carried out on the dynamic parts of the models; excitation is added to the field winding; mesh generation is carried out on the finite element model, and a solving option is defined, and comprises the simulation time of the no-load electromagnetic models, step length and motor rotating speed; leakage flux is measured quantitatively by calculating leakage inductance, the no-load leakage coefficient of the alternating-current generator is calculated, and motor structure parameter optimization is carried out according to the flux leakage problem. A novel design concept is built, the leakage flux of a permanent magnet generator is analyzed and calculated again, a magnetic structure and a control system are improved, the leakage flux of the permanent magnet generator is reduced, the running efficiency of the motor is improved, and production cost is controlled.

The invention relates to a method for quickly calculating winding temperature distribution of an oil-immersed transformer by adopting a two-dimensional axisymmetric model, and belongs to the field oftemperature rise calculation and prediction of the oil-immersed power transformer winding, and the method comprises the following steps: S1, constructing and simplifying the two-dimensional axisymmetric model of a transformer core; S2, constructing an equivalent B-H curve and carrying out frequency domain solving on the electromagnetic model; and S3, carrying out coupling calculation on the temperature by adopting a nonlinear material heat flow model. According to the method, the dimension of the transformer model is reduced through the equivalent reluctance method, the B-H curve is convertedthrough the average energy equivalent method, frequency domain calculation of the model is achieved, and the method has the advantages of being high in solving speed and precision. And the magnetic field and loss distribution rule of the transformer winding and the iron core can be quickly obtained. According to the method, coupling calculation of nonlinear materials in multiple different physicalfields is achieved, the speed and temperature of different positions in the winding are obtained, temperature distribution of the oil-immersed power transformer winding can be mastered more comprehensively, the reasonability of the transformer winding structure is better verified, and the winding insulation structure optimization design is guided.

The invention discloses an oil film thickness inversion device of a ship borne microwave scatterometer. The device comprises a microwave scattering transmitter, a microwave scattering receiver and a net device, wherein the microwave scattering transmitter transmits microwaves on the surface of a target object, and scattering lights of various angles are generated; the microwave scattering transmitter receives the scattering lights of the target object, and the obtained scattering lights are finally transmitted to the net device; the net device is an important device of microwave radio frequency circuit measurement, microwave scattering curves can be obtained through the analysis of the net device, and the oil film thickness inversion is carried out through utilizing the microwave scattering curves and a scattering electromagnetic model; and the whole device can be convenient and flexible to operate through mounting a movable window and a sliding-rail-type support on a ship. The microwave scatterometer can be applied to oil spilling detection on the sea all day and all weather, the ship borne microwave scatterometer is convenient and flexible to detect the oil spilling, and simultaneously the oil film inversion by the microwave scatterometer is relatively accurate.

The invention discloses a super electrically large size strong electromagnetic pulse environment time-frequency-space multi-dimensional analysis model. Frequency-time conversion is carried out by utilizing a ray-tracing electromagnetic pulse reconstruction method to establish a time-frequency-space multi-dimensional analysis model of a target region. The model comprises the following steps: 1) establishing a geometrical model of a super electrically large size object through related modeling software, selecting an appropriate surface element subdivision mode to generate a corresponding electromagnetic model, and electromagnetic simulation software calculating all ray paths reaching a receiving point; 2) extracting information of the ray paths and calculating a frequency domain field of each frequency of the receiving point based on a ray tracing method; and 3) obtaining time domain electromagnetic pulses at the receiving point through Fourier inverse transform. The multi-dimensional analysis model solves the problem of electromagnetic environment distribution character calculation of the super electrically large size object under the attack of an electromagnetic pulse weapon.

The invention discloses a modeling analysis method for force characteristics of a unilateral composite secondary linear induction motor. According to the invention, the simplified two-dimensional four-region electromagnetic model of the unilateral composite secondary linear induction motor is established. The magnetic field is analyzed based on the classical electromagnetic field theory. The expression of the thrust and the normal force of the motor is acquired. The relations among thrust, normal force, input current amplitude, frequency and slip ratio are studied, theoretical calculation correctness is well verified by comparing the relation with 2D and 3D finite element analysis and experimental platform test results, and the method is simple in analysis process, small in calculation amount and suitable for engineering calculation and lays a foundation for linear induction motor design.

The invention discloses a method for establishing an electromagnetic model of a full-parameter permanent magnet motor and a parameter identification method, and belongs to the field of motor control. The establishing method comprises the steps of correcting a flux linkage equation according to the influence of a saturation effect on a permanent magnet flux linkage, and on the basis, according to the influence of temperature on the permanent magnet flux linkage and stator resistance, further correcting the flux linkage equation and a voltage equation. The parameter identification method comprises the steps of establishing a thermal network by taking key components in the motor as nodes, calculating loss which obviously generates temperature rise in the motor according to a corrected electromagnetic model, distributing the loss to each node to serve as a heat source, comprehensively considering thermal resistance between the nodes and the heat source of each node, and establishing a heat transfer equation; and establishing an objective function according to the established equation, and solving the minimum value of the objective function through a temperature rise experiment, thereby identifying all the parameters to be identified in the heat transfer equation. According to the invention, the precision of the electromagnetic model is improved, the thermal network capable of accurately reflecting the thermal behavior of the motor is established, and the problem of parameter identification is solved.