20 results about "Electromagnetic current" patented technology

The invention discloses a micro-electromagnetic positioning method and system and a storage medium thereof. The method comprises the steps that sine wave current with fixed frequency sequentially, circularly and alternately passes through three groups of magnetic source micro-electromagnetic coils in sequence to excite sine wave magnetic fields in three dimensions; acquiring magnetic field data information of a positioning target in the sine wave magnetic field, and acquiring the magnetic field data information of the positioning target in the corresponding sine wave magnetic field based on the fact that one group of magnetic source micro electromagnetic coils are electrified each time, the magnetic field data information comprises a three-dimensional magnetic field component sensed by the positioning target in the sine wave magnetic field; fitting the three-dimensional magnetic field component of each dimension, and decomposing the three-dimensional magnetic field component to obtain independent magnetic field signals of three groups of magnetic source micro electromagnetic coils at the positioning target; and obtaining the position and attitude information of the positioning target according to the independent magnetic field signal. According to the invention, three-dimensional sine wave magnetic fields with fixed frequency can be excited circularly and alternately, so that a positioning target can generate three-dimensional data to facilitate positioning calculation. In addition, a function fitting mode is adopted to assist in positioning calculation, after n-point data fitting, the standard deviation of an equivalent magnetic field measurement value can be reduced to # imgabs0 # of a direct measurement result, the signal-to-noise ratio is remarkably improved, superimposed magnetic field signal data with high accuracy are extracted, and the precision of a positioning system can be improved. According to the positioning method, the system is high in anti-interference capability, the calculation result is more accurate, the overall power consumption is low, and the cost is low.

This invention discloses a method for obtaining the wide-angle single-station RCS of a medium target based on a compressed sensing algorithm. The steps are as follows: setting a wide-angle uniform incident plane wave illuminating the medium target; defining RWG basis functions and calculating the excitation vector for each incident angle; performing sparsification and compression on the excitation vectors respectively; generating the PMCHWT equations for the target surface and solving to obtain the compressed induced electromagnetic current matrix; recovering the original induced electromagnetic current matrix from each column of the compressed induced electromagnetic current matrix using the OMP algorithm; and calculating the radar cross section of the medium target based on the induced electromagnetic current vectors. This invention can obtain the RCS result at any angle with fewer PMCHWT equation solutions and combined with the OMP recovery algorithm, reducing the solution time for the wide-angle RCS of the medium target while ensuring accuracy.

The present application relates to the field of electromagnetic control technology, and in particular to an electromagnetic lock device and a control method thereof. The present application scheme detects tag information through a reader / writer, and then controls the start of a constant current driving power supply to excite the electromagnet coil, and triggers the monitoring of the time when the electromagnet current reaches a preset state, and further detects the air gap between the electromagnet and the armature based on the time to determine whether it fits. The present application scheme cleverly utilizes the inductive physical characteristics of the electromagnet, and through constant current source excitation, before the electromagnet adsorbs the armature, the electromagnet is used as an air gap type inductive sensor for detection, and the detection of whether the electromagnet fits is converted into a parameter detection of the time when the current reaches a preset state for characterization. It only needs to execute the corresponding corresponding device control to determine whether the electromagnet and the armature are completely attracted and whether they are completely in a closed state. No additional sensors are required to determine whether they are tightly closed, and it can be intelligently connected with the production control system.

The present invention discloses a method for estimating the radar cross section of a dielectric coated target, which relates to the field of radar application and is applicable to dielectric coated targets of electrically large size, and improves the calculation efficiency of the radar cross section while ensuring the calculation accuracy. The present invention is based on the characteristics of the target coating medium, and adopts a stepping method to calculate the reflection coefficient of the target surface; then the induced electromagnetic currents of different facets after the target is segmented are calculated respectively; based on the induced electromagnetic currents of different facets, the scattered electric field of each facet of the target is calculated respectively, and the scattered electric fields of the visible facets are summed to obtain the total scattered electric field of the target, and the radar cross section RCS is calculated accordingly. The present invention can be applied to the electromagnetic characteristic analysis of dielectric coated targets of electrically large size, and improves the calculation accuracy while ensuring the calculation efficiency.

The invention discloses an inter-well time-frequency electromagnetic data acquisition system and method based on an underground current source, and the method comprises the steps: employing a time-frequency electromagnetic emission source to emit low-frequency time-frequency electromagnetic signal current among two wells or multiple wells, and employing an array type multi-component time-frequency electromagnetic data acquisition short section in a receiving well, inter-well time-frequency electromagnetic signals of two wells or multiple wells are collected; as one end of the time-frequency electromagnetic emission source is arranged under the emission well, and the other end of the time-frequency electromagnetic emission source is grounded at the mouth of the receiving well or is connected to the mouth of the metal sleeve, the time-frequency electromagnetic current emitted by the time-frequency electromagnetic emission source under the emission well passes through rock stratums or reservoirs among two wells or multiple wells to reach the mouth of the receiving well or the sleeve of the receiving well; and meanwhile, a low-frequency induced polarization effect is excited in the inter-well reservoir. Due to the fact that inter-well low-frequency and time-frequency electromagnetic data are collected, the resistivity, the polarizability and the IPR distribution of rock strata between two wells or multiple wells can be calculated through constraint inversion, and accurate evaluation on oil and gas resources of underground reservoirs is achieved.

The invention particularly relates to a random response analysis method for a piezoelectric-electromagnetic hybrid energy collector under pulsating wind excitation, and the method comprises the steps: building a mechanical vibration equation containing a galloping aerodynamic item and a time-delay feedback control item, and enabling the mechanical vibration equation to be combined with a piezoelectric voltage state equation and an electromagnetic current state equation to form an initial electromechanical coupling equation set; therefore, the mechanical end dynamics and the energy conversion effect of the two branches are simultaneously represented in the same model. Introducing the dimensionless fluctuating wind speed into galloping aerodynamic force and performing equivalent modeling by using multiplicative noise so as to explicitly map the fluctuating wind speed into a state-related random excitation item; voltage and current variables are equivalent to algebraic terms of displacement and speed by adopting harmonic transformation, and an equivalent decoupling system is obtained, so that model variable transformation is realized, and the analytical solution efficiency is improved; and finally, a steady-state probability density function is obtained based on energy envelope random averaging, and a random response analysis result is calculated according to the steady-state probability density function, so that a reliable basis is provided for evaluation of control parameters and energy harvesting performance.

A non-transitory computer-readable recording medium stores a simulation program for causing a computer to execute a process including: generating thinned grids for electromagnetic current computation, according to electric field strength distribution in an equivalent electromagnetic current area; and calculating equivalent electromagnetic currents and far fields, by using the thinned grids.

The disclosure provides a compact ultra-wideband (UWB) antenna comprising a plurality of sub-radiator segments, the plurality of sub-radiator segments being a flare section, an inductive corner section, and a rib section. The inductive corner section is configured to mount to a ground surface and connects the flare section and the inductive corner section. The UWB operates over a wide frequency range of 2-18 GHz with good impedance match, high forward gain, stable phase center, and consistent radiation performance. The UWB antenna further comprises a feed point. The feed point is configured to receive a coaxial connector. The plurality of sub-radiator segments are each optimized to propagate electromagnetic currents during specific frequency ranges within the wide frequency range of 2-18 GHz. Further, the UWB antenna can be a single monolithic material, such as a metallic aluminum.

This invention provides an integrated and accurate simulation method for electromagnetic scattering of partially rotating targets, comprising: modeling and setting system parameters; dividing the target into relatively stationary sub-regions, rotating sub-regions, and linked sub-regions, and establishing a rotationally symmetric equivalent surface to completely enclose the rotating sub-domains; establishing a global coordinate system and a local coordinate system; using a consistent mesh in the global coordinate system as the outer mesh, and independently meshing the local coordinate system as the inner mesh, and defining the inner and outer basis functions accordingly; calculating the self-acting operator, equivalent operator, coefficient solving operator, and interaction operator of the equation to be solved; updating the coordinate system rotation operator between the global and local coordinate systems, establishing and solving the equation to be solved for the partially rotating conductor target at the current moment, and then calculating the far-field scattering field at the current moment from the scattering electromagnetic current coefficient vector; repeating the first two steps until the calculation of the far-field scattering field at different sampling time points throughout the entire rotation cycle is completed. This method has a fast modeling speed.

The invention discloses an electromagnetic near-field scattering characteristic modeling calculation method based on half-space target source reconstruction and electronic equipment. The method comprises the following steps: modeling the ground into an infinite PEC, and constructing a surrounding surface for a target scatterer on the ground and a ground area in contact with the target scatterer; calculating an incident field of the incident wave on the surrounding surface, and solving equivalent electromagnetic current distribution on the surrounding surface by taking the incident field as an excitation source; removing a target scatterer in the surrounding surface, and performing integration on the equivalent electromagnetic current distribution by using a half-space green function to obtain a part of scattered field at the observation position; and calculating a background field of the observation position when only the incident field is incident on the infinite ideal electric conductor ground, and adding the background field and a part of the scattered field to obtain a total electromagnetic field of the observation point. Half-space target source reconstruction is carried out based on the Huygens equivalence principle, the model complexity is greatly reduced, the operation efficiency is remarkably improved, the problem of ground truncation is solved, and meanwhile, the method is suitable for far-field and near-field scenes.

The application relates to an anti-saturation device for an electromagnetic current transformer, comprising a negative resistance circuit and a negative inductance circuit connected in series; the negative resistance circuit comprises a first resistor, a second resistor, a third resistor and a first operational amplifier, the first resistor is connected to the inverting input end of the first operational amplifier, the first resistor is also connected to the output end of the first operational amplifier, the second resistor is connected to the non-inverting input end of the first operational amplifier, the second resistor is also connected to the output end of the first operational amplifier, and the third resistor is connected to the non-inverting input end of the first operational amplifier; the negative inductance circuit comprises an inductor, a fourth resistor, a fifth resistor and a second operational amplifier, the inductor is connected to the inverting input end of the second operational amplifier, the inductor is also connected to the output end of the second operational amplifier, the fourth resistor is connected to the non-inverting input end of the second operational amplifier, the fourth resistor is also connected to the output end of the second operational amplifier, and the fifth resistor is connected to the non-inverting input end of the second operational amplifier.

The present application relates to a kind of vortex electromagnetic wave target high-frequency scattering calculation method based on equivalent edge electromagnetic current correction, belong to electromagnetic calculation field.Method includes: constructing target triangulation model and extracting convex split edge;Bessel vortex wave is decomposed into plane subwave superposition;The main scattering field under the irradiation of subwave is calculated using physical optics PO;Based on physical diffraction theory, the diffraction field of subwave in convex split edge is calculated using PTDEEC model of equivalent edge electromagnetic current;The main scattering field and edge diffraction field are superposed to obtain the modified total field, and the radar cross section (RCS) is calculated.The present application effectively corrects the diffraction error of traditional PO method at the edge of target by equivalent edge electromagnetic current, significantly improves the scattering calculation precision of large-size edge target under complex vortex beam irradiation, and provides more reliable high-frequency algorithm for radar target recognition and stealth design.

The current transformer secondary open circuit protection device is composed of a shell, a bimetallic strip, a thermal element resistance wire, a first lead, a movable contact, a static contact, a conductive metal sheet and a second lead, and has the advantages that inert gas is filled in a closed glass tube, glow discharge is generated through ionization, the bimetallic strip is heated to deform through heat of the glow discharge, and the current transformer secondary open circuit protection device is safe and reliable. The movable contact on the bimetallic strip is in contact with the static contact on the conductive metal sheet, so that the lead wire I and the lead wire II are conducted, and the K1 terminal and the K2 terminal on the secondary side of the current transformer are short-circuited, the short circuit of the open-circuit winding of the electromagnetic current transformer is achieved, high voltage generated by secondary open circuit is eliminated, and the electromagnetic current transformer has the advantages of long service life and low cost. The size is small, the mechanism is simple, and the device can be repeatedly used after faults disappear.

The present invention discloses a large-scale urban electromagnetic environment analysis method based on measurement and calculation fusion. It mainly solves the problems of high calculation cost, excessive consumption of computing resources, lack of timeliness and low accuracy in the existing technology. The implementation scheme is: extracting the coordinates of all source points and observation points in the urban environment and radiation source model diagram; using a parallel computing strategy based on a message passing interface to allocate observation points to each CPU and perform ray tracing and occlusion judgment from the observation point to the source point; using a high-order moment method to calculate the electromagnetic current on the surface of the radiation source; calculating the reflection field and diffraction field at the occlusion point based on the electromagnetic current on the surface of the radiation source, and then obtaining the simulated field intensity of the observation point by superposition of field intensity; using a spectrum sensor to measure the selected measured points in a real urban environment and using the precise measurement results to correct the simulated field intensity obtained by fusion simulation to obtain a more accurate fusion field intensity. The present invention greatly shortens the calculation time and improves the calculation accuracy, and can be used for communication spectrum planning and electromagnetic environment assessment.

The invention provides a method and a system for calculating electromagnetic scattering characteristics of a complex target and a medium. The method comprises the following steps: dividing regions according to material distribution and splitting open regions into open regions and interfaces; constructing an electromagnetic current joint integral equation based on electric field and magnetic field continuity conditions; the equation is directly adopted in an open area, and a variable coefficient is introduced into an interface to correct a Robin transmission condition; constructing a matrix equation by using a full / semi-RWG primary function and combining a Galerkin method through a triangular surface element discrete grid; and after a generalized minimum margin method is adopted for solving, a scattering field and a radar scattering sectional area are calculated. According to the method, variable coefficient DDM, non-conformal mesh generation and discontinuous Galerkin technologies are fused, the problem of discontinuity of multi-scale adaptation and matrix construction is solved, calculation precision and efficiency are both considered, and the method is suitable for rapid calculation of electromagnetic scattering of complex targets.

This invention discloses an inter-well time-frequency electromagnetic data acquisition system and method based on a downhole current source. A time-frequency electromagnetic transmitter emits low-frequency time-frequency electromagnetic signal current between two or more wells. An array-type multi-component time-frequency electromagnetic data acquisition sub is used in the receiving well to acquire the inter-well time-frequency electromagnetic signals. Since one end of the time-frequency electromagnetic transmitter is downhole in the transmitting well, and the other end is grounded at the wellhead of the receiving well or connected to the metal casing, the time-frequency electromagnetic current emitted by the transmitter passes through the rock formations or reservoirs between the two or more wells, reaching the wellhead or casing of the receiving well, and simultaneously stimulating a low-frequency excitation polarization effect within the reservoir. Because this invention acquires low-frequency inter-well time-frequency electromagnetic data, the resistivity, polarizability, and IPR distribution of the rock formations between the two or more wells can be calculated through constrained inversion, enabling accurate evaluation of the oil and gas resources in the underground reservoirs.

The invention relates to a vortex electromagnetic wave target high-frequency scattering calculation method based on equivalent edge electromagnetic current correction, and belongs to the field of electromagnetic calculation. The method comprises the following steps: constructing a target triangulation model and extracting a convex split edge; decomposing the Bessel vortex wave into planar wavelets for superposition; calculating a main scattering field under wavelet irradiation by adopting a physical optical method PO; calculating a diffraction field of the wavelet on the convex split edge based on a physical diffraction theory equivalent edge electromagnetic current PTDEEC model; and superposing the main scattering field and the edge diffraction field to obtain a corrected total field, and calculating a radar cross section (RCS). According to the method, the diffraction error of a traditional PO method on the edge of the target is effectively corrected through the equivalent edge electromagnetic current, the scattering calculation precision of the electrically large-size edge target under the irradiation of the complex vortex beam is remarkably improved, and a more reliable high-frequency algorithm is provided for radar target recognition and stealth design.

This application provides a harmonic elimination method and apparatus for modular multilevel converter high-voltage direct current (HVDC) transmission, comprising: constructing a current and voltage measurement matrix based on the topology and electrical parameters of an electromagnetic current transformer, its secondary system, an electromagnetic voltage transformer, and its secondary system in the HVDC transmission system; constructing an HVDC transmission impedance model including current and voltage measurement components based on the main circuit topology of the HVDC transmission system and the current and voltage measurement matrix; analyzing the HVDC transmission impedance model under preset operating conditions to obtain the impedance matrix of the current and voltage measurement components; and determining the resonant frequency of the HVDC transmission using the impedance matrix of the current and voltage measurement components to perform harmonic elimination. This application can analyze the mismatch effects caused by the measurement components of the current transformer (CT) and its secondary system, and the current transformer (PT) and its secondary system, respectively, determine the system resonant frequency, and eliminate the resonance effect.

The present invention proposes a method and device for detecting the gap of a high-temperature gas-cooled reactor electromagnetic bearing. The method controls the rotor of the high-temperature gas-cooled reactor electronic bearing to suspend in an auxiliary bearing ring through an electromagnet, and moves along the axial direction of the auxiliary bearing, measures the gap value between the rotor and the auxiliary bearing, constructs a linear relationship between the electromagnet current and the spacing between the rotor and the auxiliary bearing of the high-temperature gas-cooled reactor electromagnetic bearing, and establishes a mapping table; in the same batch of electromagnets controlling the working process of the high-temperature gas-cooled reactor electronic bearing, the electromagnet current and the spacing between the rotor and the auxiliary bearing of the corresponding high-temperature gas-cooled reactor electromagnetic bearing are collected in real time, and the gap value corresponding to the collected electromagnet current in the mapping table is queried to determine whether the two are the same. Through the present invention, the on-site debugging and maintenance time can be greatly shortened, the debugging and maintenance efficiency and economy can be improved, and the operation reliability of the electromagnetic bearing system can be improved.

The invention discloses a residual magnetism detection and demagnetization method and device for an iron core of an electromagnetic current transformer. The method comprises the following steps: collecting a current signal and a voltage signal; performing harmonic analysis on the current signal; carrying out integration processing on the voltage signal; performing phase decomposition on the even harmonic component according to a magnetic flux fundamental wave phase, and extracting a residual magnetism correlation component; determining a normalized residual magnetism index according to the residual magnetism correlation component and the odd harmonic component; the controllable current source is connected in parallel with a secondary loop of the electromagnetic current transformer; and taking the normalized residual magnetism index as a closed-loop feedback signal to adjust the polarity and amplitude of the controllable direct-current component, so that the normalized residual magnetism index approaches zero. On the premise that the electromagnetic current transformer does not exit from operation and metering and protection functions of the electromagnetic current transformer are not interrupted, whether residual magnetism exists in the iron core or not and the level of the residual magnetism can be detected on line, closed-loop active demagnetization is automatically implemented when it is detected that the residual magnetism exceeds a safety threshold value, and the iron core is restored to a symmetrical magnetization working state without residual magnetism.