Characteristics Of Electromagnetic Field Research Articles

Height and Angle Characteristics of Point Source Transmitting Power of Wireless Avionics Intra-Communication Systems Based on FDTD Analysis

The equivalent isotopically radiated power (EIRP) of a wireless avionics intra-communication (WAIC) system is limited to 6 dBm/MHz at the geometrical center of the aircraft, to avoid interference with aircraft radio altimeters, which are operated at the same frequency band between 4,200–4,400 MHz. In this paper, the height and angle characteristics of the point source EIRP of a WAIC system are analyzed based on the large scale FDTD analysis. Firstly, the strength of the electric field (E-field) around the three-dimensional model of Airbus A320-200 is analyzed. Then, the point source EIRP is calculated based on the analyzed E-field strength. Finally, the height and angle characteristics are analyzed to estimate the electromagnetic field characteristics of the aircraft.

Model of Charged Anisotropic Strange Stars in Minimally Coupled f R Gravity

In the present article, we have investigated a new family of nonsingular solutions of static relativistic compact sphere which incorporates the characteristics of anisotropic fluid and electromagnetic field in the context of minimally coupled f R theory of gravity. The strange matter MIT bag model equation of state (EoS) has been considered along with the usual forms of the Karori–Barua KB metric potentials. For this purpose, we derived the Einstein–Maxwell field equations in the assistance of strange matter EoS and KB type ansatz by employing the two viable and cosmologically well-consistent models of f R = R + γ R 2 and f R = R + γ R R + α R 2 . Thereafter, we have checked the physical acceptability of the proposed results such as pressure, energy density, energy conditions, TOV equation, stability conditions, mass function, compactness, and surface redshift by using graphical representation. Moreover, we have investigated that the energy density and radial pressure are nonsingular at the core or free from central singularity and always regular at every interior point of the compact sphere. The numerical values of such parameters along with the surface density, charge to radius ratio, and bag constant are computed for three well-known compact stars such as CS1 SAXJ 1808 . 4 − 3658 ( x ˜ = 7.07 km , CS2 VelaX − 1 x ˜ = 9.56 km , and CS3 4U1820 − 30 x ˜ = 10 km and are presented in Tables 1–6. Conclusively, we have noticed that our presented charged compact stellar object in the background of two well-known f R models obeys all the necessary conditions for the stable equilibrium position and which is also perfectly fit to compose the strange quark star object.

Analysis of Methods for Determining the Characteristics of a Single Spatial Electromagnetic Field

This paper analyzes the methods for determining the characteristics of a single spatial electromagnetic field; considerations combine all–electric, magnetic, and electromagnetic fields into a single electromagnetic theory of a spatial field. On the basis of the concept of a single field of force spatial interaction of material bodies, it is analytically established that in a physical vacuum only waves of its polarization actually exist, transporting in the space of a vacuum sphere its excitation energy, which when force interacting with a certain physical characteristic (electrical, magnetic or gravitational) material body, creates a dynamic response of the parameters of this body, which is recorded in the experiment as a real flow of energy with responsible of the physical nature.

Simulation Research on Distribution Characteristics of Electromagnetic Field of AC UHV Transmission Line

With the development of UHV and long-distance power transmission technology in my country's power grid, the electromagnetic environment of 100kV UHV transmission lines will be one of the key issues affecting the feasibility of UHV transmission. The impact of low-frequency noise from UHV AC transmission lines on the lives of residents along the corridor should not be ignored. In particular, pure AC sound attenuates slowly along the line and spreads far away, which often has more serious impacts on the lives of nearby residents. In order to study the distribution law and influence degree of pure sound, this article mainly conducts a more in-depth study on the wiring method of UHV transmission lines through theoretical calculation and computer simulation.

A Study on External Electromagnetic Characteristics of Underground Cables With Consideration of Terminations

The characteristics of external electromagnetic fields (EEMFs) produced by underground cables in the lossy earth are further investigated and studied. This paper develops an excitation current in the cables with the bi-directional propagation for the calculations of the vectors of EEMFs. By adopting the newly proposed method in this paper, it allows the considerations of the terminating conditions and the lengths of the cable on the calculations of the vectors of EEMFs. Moreover, the vectors of EEMFs are calculated, compared and discussed using various load/source impedances. The effects of lengths of underground cables on the vectors of EEMFs are studied. Also, the frequency-dependent earth models are included into the investigations of the EEMFs. The results presented in this paper are compared and verified with the Numerical Electromagnetics Code.

Distribution Characteristics of Electromagnetic Field and Temperature Field of Different Caliber Electromagnetic Railguns

To explore the influence of different caliber on the electromagnetic field and temperature field of railguns, an electromagnetic-thermal coupling analysis is carried out on three kinds of caliber railguns by Maxwell 3-D and ANSYS Workbench. The current density and temperature distribution on the contact surface between armature and rails of three kinds of caliber railguns are obtained, respectively. The calculation results show that the maximum current density and temperature of the small and medium caliber railguns appear on the contact surface, but the large caliber railgun appears to the armature throat. As the caliber increases, the current density and temperature on the contact surface have decreased significantly. The maximum current density of medium and large caliber railguns decrease by 13.7% and 35.5% compared with small caliber railgun, and the maximum temperature decrease by 38.8% and 50.1%, respectively. The temperature of the small caliber railgun rises fastest, which is 1.87 and 1.61 times that of the medium and large caliber railguns, respectively. The results can provide an important basis for the design of large caliber electromagnetic railgun.

Research on the electromagnetic propagating characteristics of hypervelocity impact on the target with aperture and different potential conditions

In view of the key problems of the discharge phenomenon caused by the impact of small space debris on the satellite's charged surface and the electromagnetic field induced entering the interior of the satellite after coupling through the aperture. In this paper, the characteristics of the coupling plasma, the plasma induced discharge and the propagation of the electromagnetic field induced by discharge through the aperture are studied by using the two-stage light gas gun loading system, the discharge charge monitoring system, the plasma diagnosis system and the electromagnetic testing system; Combined with the characteristic parameters of plasma inside and outside the Simulated satellite, the curves of discharge current and voltage, and the spectrum characteristics of electromagnetic radiation inside and outside the simulated satellite, the characteristics of electromagnetic field propagating into the Simulated satellite through the aperture under different potential on the surface of the simulated satellite are analyzed. The experimental results show that the characteristic parameters of the ionized plasma produced by the ionization of the target and the projectile splash increase with the increase of the surface potential of the target, and the ionized plasma determines the discharge characteristics and electromagnetic field characteristics; After the electromagnetic field generated by the impact side propagates through the aperture into the inner of the simulated satellite, the electromagnetic field in the simulated satellite appears signal attenuation in most frequency bands, but signal enhancement occurs in a few frequency bands; The main reason of electromagnetic signal attenuation is that the electromagnetic field directions at the edge of the aperture and the back of the target are opposite to that at the impact side; The enhancement of electromagnetic signals in some frequency bands is caused by the plasma entering the simulated satellite.

Electromagnetic interference characteristics during switching operation in power distribution network

The disturbance problem caused by the transient electromagnetic field during high-voltage switching operation is the most typical. Electromagnetic interference can be coupled to the secondary circuit in a conductive and radiating manner, then, affects the reliability of the secondary-side circuit. The key to the simulation calculation of the operating switch overvoltage is the judgment and simulation of its opening and closing conditions. The arc current zero-crossing judgment signal, the arc extinguishing and reignition judgment signals are fused, and a control signal is recursively obtained for switching operation. By analyzing the transient process during switch operation, a simplified model for isolating and closing the no-load bus, an overvoltage calculation model, and a fast transient model for overvoltage time-frequency signals are established. The characteristics of the transient electromagnetic field generated when the no-load bus and the circuit breaker of the disconnector are charged to the no-load transformer are simulated. The mechanism of fast transient pulse group generated by switching operation is obtained. The maximum overvoltage amplitude generated during the disconnector’s switching, and the no-load bus is obtained by simulation. Comparing with the measured data, the laws of electromagnetic interference characteristics during switching operation in power distribution network are verified.

Technical Possibilities for Implementing Measures to Reduce the Emitted Electromagnetic Field of a High-voltage Distribution Transformer

This paper deals with the measurement of electromagnetic field parameters near high voltage systems, characteristics of electric field, magnetic field and electromagnetic field, as well as the possibilities of implementing measures to reduce the emitted electromagnetic field. The paper describes the measurement of electromagnetic field parameters in the vicinity of high voltage systems, the analysis and synthesis of the measurement results in the external and internal environment of particular transformer stations is evaluated. The objects of interest in these measurements were brick transformer stations for transforming AC voltage from 22 kV to 400 V and 230 V at the operating frequency of 50 Hz. With regard to the influence of electromagnetic fields in the environment, individual measurements were assessed in accordance with selected criteria.

Research on the Electromagnetic-Heat-Flow Coupled Modeling and Analysis for In-Wheel Motor

In this paper, a 15 KW in-wheel motor (IWM) is taken as the research object, and the coupling factors among the electromagnetic field, temperature field and flow field are analyzed, and the strong and weak coupling factors between the three fields are clarified, and by identifying the strong and weak coupling factors between the three fields, a three-field coupling analysis model for IWM with appropriate complexity is established, and the validity of the model is verified. In a certain driving condition, the electromagnetic field, temperature field and flow field characteristics of IWM are analyzed with the multi-field coupling model. The result shows that, after the IWM runs 8440 s under driving conditions, in this paper, the IWM electromagnetic torque of the rated working condition is 134.2 Nm, and IWM the electromagnetic torque of the peak working condition is 451.36 Nm, and the power requirement of the motor can be guaranteed. The highest temperature of the IWM is 150 °C, which does not exceed the insulation grade requirements of the motor (155 °C), the highest temperature of the permanent magnet (PM) is 65.6 °C, and it does not exceed the highest operating temperature of the PM, and ensures the accurate calculation of components loss and the temperature of the motor. It can be found, through research, that the electromagnetic torque difference between unidirectional coupling and bidirectional coupling is 3.2%, the maximum temperature difference is 7.98% in the three-field coupling analysis of IWM under rated working conditions. Therefore, it is necessary to consider the influence of coupling factors on the properties of motor materials when analyzing the electromagnetic field, temperature field and flow field of IWM; it also provides some reference value for the simulation analysis of IWM in the future.

Numerical Simulation of the Plane Electromagnetic Wave Transient Propagation in Lossy Medium

In the field of geophysical exploration, it is of great value to study the transient propagation characteristics of electromagnetic waves in lossy medium. The equations of electric field and magnetic field are derived. The absorbing boundary conditions and numerical stability conditions are analyzed. The two-layer medium model is established to simulate the propagation characteristics of plane waves. The simulation results show that the transient analysis of electromagnetic wave propagation can reflect the time fluctuation characteristics of electromagnetic field in multilayer media, and provide the indication of the boundary position.

Distribution Characteristics and Edge Detection of Electromagnetic Field in Two Beds Formation Based on Analytical Solution

After decades of development of the Chinese petroleum industry, complex oil and gas reservoirs have become the main battlefield for oil and gas field detection and development, which pose severe challenges to geosteering drilling technology that uses integrated logging and conventional logging-while-drilling tools to locate and predict formation interfaces. Based on the developed software for the distribution of forward and lateral detection electromagnetic fields, this paper calculates and analyzes the distribution characteristics of electromagnetic fields at different distances in front, and studies the lateral detection characteristics based on the half-coil of the electric field. The results show that the influence of boundary on the field is revealed according to the distribution characteristics of electromagnetic fields at different distances in front. The 1-3m receiving-transmitting short-pitch half-coil have approximately the same edge detection distance, and when the frequency is less than 20 kHz, the edge detection distance is more than 30m in two beds formation of 0.01S/m and 1.0S/m.

ЗАГАЛЬНІ ЗАСАДИ ПРОЕКТУВАННЯ ЕЛЕКТРОМАГНІТНИХ ЕКРАНІВ ТА ЕКРАНУЮЧИХ КОНСТРУКЦІЙ

В умовах складної електромагнітної обстановки, що формується за рахунок впливу зовнішніх та внутрішніх джерел, а також внаслідок широкого застосування бездротових систем передачі інформації, завдання, пов’язані із застосуванням екрануючих конструкцій значно ускладнюються. Зокрема, необхідність забезпечення стабільної роботи мобільного зв’язку накладає певні обмеження на коефіцієнти екранування захисних матеріалів. Це потребує визначення загальних підходів до запровадження екранування на принципах розумної достатності, враховуючи як захист людей від електромагнітних впливів, так і виробничі потреби. Встановлено, що необхідним є розроблення схеми проектування електромагнітних екранів з урахуванням складності електромагнітної обстановки. Мета роботи – розроблення загальних засад проектування екрануючих матеріалів та конструкцій з урахуванням гранично допустимих рівнів магнітних та електромагнітних полів різного походження. Обґрунтовано, що для проектування магнітних та електромагнітних екранів доцільно використати експериментальні дані щодо залежності коефіцієнтів екранування від товщини захисного матеріалу, вмісту екрануючої металевої та металовмісної субстанції у полімерній матриці тощо. Визначено коефіцієнти екранування магнітного поля промислової частоти, електромагнітного поля частотою 1,8 ГГц та геомагнітного поля композиційними металополімерними матеріалами різної товщини та характеристик. Встановлено, що оптимізація параметрів матеріалів щодо впливів полів цих трьох походжень неможлива. Наведено схему, яка може бути використана за наявності електромагнітних полів різного походження та широкого частотного спектра. Але передумовою таких робіт є проведення моніторингу електромагнітної обстановки у виробничих приміщеннях з визначенням амплітудно-частотних характеристик електромагнітних полів різного походження. Здійснення проектних та впроваджувальних робіт за розробленою схемою є найбільш доцільним підходом щодо проектування захисних матеріалів та екрануючих конструкцій. Такий підхід мінімізує витрати часу та коштів на роботи з електромагнітної безпеки

Response characteristics of transient electromagnetic of fault structures in shallow stratum of underground space and its exploration

The key to detecting underground faults in shallow stratum of the city with transient electromagnetic method is the determination of the fault location and the characteristics of accurate underground parameters. In order to establish a field data acquisition device and method parameters suitable for the exploration of the fault structure in the shallow layer of the city, the corresponding numerical model is established based on the Shungeng mountain fault structure with shallow depth. The finite difference method is used to simulate and calculate the response characteristics of the transient electromagnetic field in the fault structure zone, which provides the basis for the field application of the method and technique. Then, based on the surface geological conditions of Dongshan section of the Shungeng mountain fault, by using the short-circuit transient electromagnetic method, field data acquisition observing system and relevant parameters suitable for transient electromagnetic prospecting of urban shallow fault structures were established through experiments on site technical conditions, and the geoelectric section. The structure and characteristics of shallow buried faults are judged and explained. The results show that the response characteristics of transient electromagnetic in the fault fracture zone are significant, and the location and structure of transient electromagnetic field can be easily distinguished. It can provide references for similar geological conditions.

Three-Dimensional Magnetostatic Waves Caused by Electromagnetic Fields in Metallized Ferrite Plates

By using a well-known technique for finding the characteristics of magnetic fields based on the method of decomposition of unknown quantities in a series in small parameter (chosen as the ratio of amplitude of the tangential harmonic field to the amplitude of normal constant field) and restricting ourselves to the first two terms of decomposition, we establish the conditions of excitation and study the regularities of propagation of three-dimensional magnetostatic waves in metallized normally magnetized ferrite plates depending on the character of the external electromagnetic field and electrophysical characteristics of the material.

A Novel Coupler Design and Analysis with Shielding Material Tests for a CPT System of Electric Vehicles Based on Electromagnetic Resonant Coupling

In this paper, a contactless power transfer (CPT) system using a novel geometrically enhanced energy transfer coupler with three different shielding materials has been built and analysed, along with the evaluations from aspects of electromagnetics and RMS power transmitting based on electromagnetic resonant coupling. A CPT system design improvement with the proposed H-shape ferromagnetic cores and the combined semi-enclosed passive electromagnetic shielding methods have been investigated in terms of generated electromagnetic field characteristics, system power transfer ratings, system efficiency optimization and performances of shielding materials. The results have shown that, across the range of operating frequency of the CPT system, aluminium shielding as a metallic material method could deliver better overall CPT system performance than other two ferromagnetic materials, steel 1010 and ferrite. In addition, the coupler prototype design limitations, misalignment tolerance and the passive shielding design considerations including distance between windings and inner surfaces of shielding shells have been discussed.

Antenna pairing for highly efficient wireless power transmission in the reactive near‐field region based on mutual coupled impedance compensation

This study presents the design of an antenna pair for short-distance wireless power transmission (WPT) in the reactive near-field (NF) region. Instead of designing each antenna alone to achieve good reflection coefficients, the transmitting (TX) and receiving (RX) antennas as a pair are designed to maximise the transmission coefficients. Thus, the antenna pair can mutually compensate the impedance mismatching caused by the coupling between them to enhance energy transfer efficiency. Based on this concept, the developed RX antenna, a key component of rectennas, has a dual functionality to retain relatively stable reflection coefficients when it is moved far away from the NF TX antenna, for example, to pair with other conventional far-field WPT TX antennas with larger separation distances. The electromagnetic field and energy transfer characteristics, as well as system experiments, are presented to validate the design.

Effect of Condensed Phase Particles on the Electromagnetic Field Characteristics of Combustion Products in a Flow Path of a Liquid-Propellant Engine. The Results of Experimental Studies

This paper describes the experimental study of amplitude (with a frequency of up to 50 kHz) and integral characteristics of the self-magnetic field of high-temperature combustion products of hydrocarbon fuel, which flow out of the nozzle of a standard liquid-propellant engine (LPE) with simulation of the heat of a combustion chamber with injection of aluminum-magnesium alloy particles (c-phase) into the combustion chamber. It is determined that the amplitude of the magnetic field intensity generated by high-temperature (up to 3500 K) combustion products depends on the LPE operation modes and the presence of k phase particles in the particle flow. The magnetic field amplitude increases by 20% during the LPE burnout ≈0.2 s earlier than the pressure drop in the combustion chamber. The total volumetric electric charge generated by the combustion product flow with the c-phase is estimated.

Analysis on Electromagnetic Field of Continuous Casting Mold Including a New Integral Method for Calculating Electromagnetic Torque

Based on the Maxwell’s equations, a finite element model is established to study the characteristics of electromagnetic field in the mold of billet and bloom continuous casting with electromagnetic stirring (M-EMS). A novel integral method for calculating electromagnetic torque is proposed to evaluate the stirring intensity of stirrer. In order to verify the accuracy of the model, a well-designed electromagnetic torque detecting device is fabricated. The predicted value of electromagnetic torque and magnetic flux density are consistent with the measured data. The optimum frequency is determined by the maximal electromagnetic torque of the strand. The effect of stirring current intensity and different stirrer positions along the length of mold on the electromagnetic field has been studied numerically. The results show that the optimum frequency is smaller when the copper tube of the mold is thicker and the section size is bigger. Besides, the electromagnetic torque of the strand is a quadratic function of the running current intensity. Moreover, the installation position of stirrer strongly affects the prediction of electromagnetic field distribution, further influencing the optimum frequency and the electromagnetic torque of strand.

Suppression effectiveness research on multi-level EMI filter in thermal electromagnetic interactive filed of explosion-proof three-level NPC converter

As a system, the explosion-proof three-level NPC (Neutral-Point-Clamped) converter has the characteristics of nonlinear, high complexity, and multiple thermal electromagnetic fields, among which multiple magnetic fields interfere with each other and affect the system stability. In order to solve this problem, the conducted electromagnetic interference principle was analyzed in the converter filed firstly in this paper, and transmission paths were illustrated as well. Secondly, on the basis of IGBT (Insulated Gate Bipolar Translator) transient state analysis, the EMI (Electro-Magnetic Interference) mechanism analysis of three-level converter power devices was completed for EMI filter design. Finally, a novel multi-level EMI filter was designed to weaken mutual interference of small magnetic field group in the system and to solve the EMI suppression problem of inner cavity interaction of explosion-proof three-level NPC converter. The research target is to optimize the filter and enhance the system ability of resistance to thermal and electromagnetic interference. The suppression effectiveness of multi-level EMI filter was proved by the experiment conducted on a 1 MW (Million Watt) explosion-proof three-level NPC converter platform.