Electromagnetic Components Research Articles

Seasonal and Interannual Variations in the Schumann Resonance Observed in the ELF Electromagnetic Networks in China

AbstractBased on 9 years of quasi‐continuous data observed at extremely low‐frequency electromagnetic stations, the long‐term variations of Schumann resonances (SRs) are compared and analyzed. We obtained two major parameters, namely the peak intensity and peak frequencies by Lorentz fitting and focus on their seasonal and interannual variations of the first three modes in 10 stations. Fengning station was taken as an example to show the seasonal variations of the intensity and frequency of each electromagnetic component and each mode of SR, with the intensity reaching the maximum in Northern Hemisphere summer and minimum in winter; while the frequency has an inverse phase. And the amount they change from summer to winter also shows different characteristics. The interannual variation of the 10 stations shows the unified law of change in the magnetic field than in the electric field. Finally, in conjunction with observations from other regions of the globe, the periodic intensity variation and migration of the lighting activities were considered the dominant controlling factors for the SR parameters. And by comparing with the El Niño index and solar X‐radiation flux, the strong links between SR parameters and the 11‐year solar cycle are confirmed, and intensity enhanced under the influence the 2015/2016 super E1 Niño phenomenon.

INFLUENCE OF CONTROL CURRENT WAVEFORM ON ROTOR NUTATION OF THREE-DEGREES-OF-FREEDOM ELECTRIC MACHINE

The design of the electric machine with three degrees of freedom of the rotor with an external magnetic core, containing permanent magnets, and an internal magnetic core is considered. The both magnetic cores are rotating. The stator windings (control winding and two-phase rotation winding) are located in the air gap between the magnetic cores. The windings are powered by alternating current of corresponding phase. The positive property of rotor gyrostabilization in such structure is shown. At the same time, the negative fact consists in the nutation under the conditions of forced change in the orientation of rotation axis. There are no magnetic losses in the structure due to synchronous rotation of both external and internal magnetic cores. The immobility of the center of mass is assumed. There are no losses that give a non-conservative mechanical system. The mathematical model of the mechanic system and magnetic field is developed to compute the electromagnetic torques acting on the rotor. The expressions for electromagnetic torque components are obtained to use them in the Comsol Multiphysics interface. The effect of the sinusoidal and pulse currents in the control winding on the nutation swing is studied. The optimality of the control winding supplied by undisturbed sinusoidal current or the pulse current having square-wave length of about one-third of the period is revealed. References 15, figures 6, table 1.

Analytical Calculation and Low-Order Component Optimization of Axial Electromagnetic Force for an Axial Flux Motor

The low-order high-amplitude component of axial electromagnetic force is the leading cause of electromagnetic vibration and noise of axial flux permanent magnet (AFPM) motors. In this paper, based on the analytical calculation of the axial electromagnetic force for a 20-pole 24-slot AFPM motor, the low-order axial electromagnetic force component is weakened by optimizing the motor’s electromagnetic structure. First, the three-dimensional (3-D) structural model of the motor is equated to a two-dimensional (2-D) analytical model, which is used to calculate the magnetic field generated by each of the armature winding and permanent magnet. Then, combined with the Maxwell tensor method, the axial electromagnetic force waveform is further obtained, and the target low-order high-amplitude component is extracted by 2-D Fourier analysis. Finally, taking this axial electromagnetic force component minimization as the target function of optimization, considering the output torque and ripple as constraints, the genetic algorithm is used to search for the optimal point by varying the structural parameters of the motor. The results show that the target low-order high-amplitude component of the axial electromagnetic force of the optimized motor is effectively suppressed, and the output torque ripple decreases with slightly increased torque amplitude, which provides a practical method for vibration and noise reduction of AFPM motors.

Analysis and Application of the Electromagnetic Wave Propagation, Fields, and Dispersion Relation in an Elliptical Chiro Plasma Waveguide Immersed in Magnetized Plasma

AbstractThis research proposes and investigates an elliptical waveguide filled with chiro plasma as its core and magnetized plasma as its clad region. The clad region is in the constant infinite magnetic field, and its direction is the same as the wave propagation in the chiro plasma elliptical waveguide. The electromagnetic wave propagation in the considered waveguide is studied. The expressions for electromagnetic field components in the chiro plasma core and magnetized plasma cladding are derived. The dispersion relations for the hybrid modes are calculated considering appropriate boundary conditions at the chiro plasma and magnetized plasma interface. The behavior of the energy flux and the dispersion curves are numerically and graphically studied. It is seen that the magnitude of the power density decreases with the increase of the cyclotron frequency and it increases with the increase of the plasma frequency and supports power flow in the backward direction for the considered mode. Furthermore, it is shown higher values of the chirality parameter cause the magnitude of the power flux to increase in the backward direction.

ELECTROMAGNETIC FIELD IMPROVEMENT IN PERMANENT MAGNET SYNCHRONOUS MOTOR

Permanent magnet synchronous motors (PMSMs) have recently been popular and widely used for electrical vehicle developments in the automobile industry to replace internal combustion engines due to their ability to perform at higher efficiency. This paper uses the PMSM in fuel cell vehicle electric air compressors. To ensure that the PMSM performs at higher efficiency, some field performance, such as electromagnetic field, must be improved. In this paper, a comparison between the electromagnetic forces components in the presence of current harmonic. The data indicates that the amplitude of electromagnetic forces for both radial and tangential components are not the same, particularly in lower orders. However, radial forces contribution is greater than tangential forces. A structural optimization method reduces the radial electromagnetic (RE) forces to improve PMSMs efficiency. The optimization method involves changes in the PMSMs design values and improving the electromagnetic field performance. The RE forces found to dominate the tangential electromagnetic (TE) forces, and it is amplitudes corresponding to 2,4 and 6-order are minimized by 31.1%, 28.5%, and 15.9%, respectively. KEYWORDS: Tangential electromagnetic forces; radial electromagnetic forces; permanent magnet synchronous motor; optimization

Nonlinear Vibration Isolation of Spacecraft System by a Bionic Variable-Stiffness Device Enhanced by Electromagnetic Component

Nonlinear Vibration Isolation of Spacecraft System by a Bionic Variable-Stiffness Device Enhanced by Electromagnetic Component

DEVELOPMENT OF A TESTER FOR DIAGNOSTICS OF CABLE LINES STATE WITH XLPE INSULATION

Link for citation: Konev A.A., Khakimyanov M.I. Development of a tester for diagnostics of cable lines state with XLPE insulation. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 9, рр. 216-223. In Rus. Relevance. The moral and physical deterioration of cable lines voltage of 6–10 kV in our country ranges from 40 to 80 %. At the same time, up to 63 % of all accidents in electrical equipment are due to cable line failures. Recently, cables with cross-linked polyethylene insulation have been actively used, for the diagnosis of which special approaches are required. Therefore, the issues of developing high-voltage test facilities for diagnosing the state of insulation of electrical equipment are quite relevant. The authors proposed an original design of a high-voltage test facility that allows generating both direct voltage and alternating voltages of industrial and ultra-low frequencies. A feature of the device is the use of a multifunctional integrated electromagnetic component in it, which combines the functions of both an inductor and a capacitor. The use of this component allows reducing the dimensions and weight of the test facility. The main aims of the research are to develop a design of a high-voltage test facility and to study its characteristics; build a mathematical model and get dependency graphs. Objects: cables with XLPE insulation, high voltage test facilities. Methods: theory of electrical circuits, mathematical modeling, program for mathematical and engineering calculations Mathcad, MATLAB Simulink. Results. The authors proposed the original design of a high-voltage test facility, which makes it possible to generate both direct voltage and alternating voltages of industrial and ultra-low frequencies. The simulation of the installation was carried out. A method for calculating high-voltage test facilities is proposed.

Cosmic ray measurements with IceCube and IceTop

IceCube is a cubic-kilometer Cherenkov detector in the deep ice at the geographic South Pole. The dominant event yield in the deep ice detector consists of penetrating atmospheric muons with energies above approximately 300 GeV, produced in cosmic ray air showers. In addition, the surface array, IceTop, measures the electromagnetic component and GeV muons of air showers. Hence, IceCube and IceTop yield unique opportunities to study cosmic rays with unprecedented statistics in great detail. We will present recent results of comic ray measurements from IceCube and IceTop. In this overview, we will highlight measurements of the energy spectrum of cosmic rays from 250 TeV up to the EeV range and their mass composition above 3 PeV. We will also report recent results from measurements of the muon content in air showers and discuss their consistency with predictions from current hadronic interaction models.

A matrix differential operator for passage from scalar to vector wave optics

One possible way to generalize scalar to wave optics, thus including polarization in the treatment consistent with the Maxwell equations was shown by Mukunda, Simon and Sudarshan (MSS) for paraxial systems, based on a group theoretical analysis. Later, the MSS theory for the passage from the Helmholtz scalar wave optics to the Maxwell vector wave optics was derived by casting the basic formalism in a framework very similar to the Dirac electron theory. Here, we show that the elegant MSS substitution rule is equivalent to a second-order 6 × 6 matrix differential operator for passage from scalar to vector wave optics. We explicitly obtained this matrix differential operator in a series and exponential forms respectively. Expressions for the electromagnetic field components are derived without making any assumptions on the form of the transverse beam profile. It is observed that all types of beams have certain characteristic relations among their field components. The power of the formalism is demonstrated by considering five specific beams.

Vectorial EM Propagation Governed by the 3D Stochastic Maxwell Vector Wave Equation in Stratified Layers

The modeling and processing of vectorial electromagnetic (EM) waves in inhomogeneous media are important problems in physics and engineering, and new methods need to be developed to incorporate novel vector sensor technology. Vectorial phenomena of EM waves in stratified atmospheric layers can be incorporated into governing equations by retaining the gradient of the refractive index when deriving the Maxwell Vector Wave Equation (MVWE) from Maxwell’s equations. The MVWE, as opposed to the scalar wave, Helmholtz, and paraxial equations, couples the EM field components in inhomogeneous media and thus captures important physics phenomena such as depolarization. Here, recent developments are reviewed on using sensor time series data to reconstruct electromagnetic waves that propagate through stratified media. In modern applications, often many sensors can be deployed simultaneously to observe electromagnetic waves. These networks of sensors can be used to improve the quality of the reconstructed EM wave fields and cross-validate the observed sensor time series. Lastly, the effects of noisy current densities on sensor time series are considered. Generally, as the sensor observes for longer periods of time, the variance of estimates of the wave field obtained from sensor time series data increases. As a result, longer sensor observation times do not always result in better estimates of the EM wave fields, and an optimal observation time can be obtained.

Constructing honeycomb-like hierarchical foam via electromagnetic cooperation strategy for broadband microwave absorption

The application of wireless electronic devices inevitably leads to electromagnetic pollution. Three-dimensional porous foam structures have been shown to be an effective strategy to construct high-performance microwave absorbers. Herein, the honeycomb-like hierarchical foams were fabricated via melamine-formaldehyde (MF) foam as substrate coupled with flaky carbonyl iron (CI)-MXene lamellae. Inside the synthesized composite foam, flaky CI is interlaced into MXene nanosheets to form hierarchical structures, which effectively alleviates the originally self-stacking phenomenon and provides numerous heterogeneous interfaces, resulting in the optimization of impedance matching. In addition, owing to the construction of consecutive electromagnetic networks, the CI-MXene/MF foams exhibit significant dielectric loss and magnetic loss capability. Moreover, the honeycomb-like structure offers multiple reflections/scattering for electromagnetic waves, which effectively prolongs the transmission paths, further improving the microwave attenuation ability. Hence, the synthesized composite foam exhibits superior microwave absorption performance with a minimum refection loss of −61.4 dB and a maximum effective absorption band of 7.18 GHz. The construction of unique microstructure and regulation of electromagnetic components is demonstrated to be feasible strategies for the design of efficient microwave absorbers in future.

Mathematical and Physical Modeling of a Low-Pass Filter Based on a Multifunctional Integrated Electromagnetic Component

Mathematical and Physical Modeling of a Low-Pass Filter Based on a Multifunctional Integrated Electromagnetic Component

РЕЗОНАНСНА СИСТЕМА БЕЗДРОТОВОЇ ПЕРЕДАЧІ ЕНЕРГІЇ З ВИКОРИСТАННЯМ ЕЛЕКТРИЧНОГО ПОЛЯ

The paper reviews the existing types of wireless technologies for power transmission using electromagnetic interaction. According to the type of interaction, systems using magnetic, electric and electromagnetic components are distinguished. Short-range, medium-range and long-range systems are distinguished by range. As promising for implementation in future unmanned systems, the work considers a modified system of wireless transmission of electrical energy using an electric field. The scheme is presented and the principle of operation of such a system is considered. The characteristics of resonant circuits used as emitters and receivers in such a system were studied. The results of measuring the parameters of the spatial distribution of the electric field of the resonators are presented. The interaction of the spectral components of the input signal and the resonant characteristics of the radiating circuits was investigated. The paper presents the method of determining the efficiency of electric energy transmission at high frequencies and the results of measurement of transmission efficiency for the studied type of systems. It was concluded that there is an active factor in the form of an alternating electric field, the feature of which propagation allows creating a device suitable for powering unmanned mobile systems of low and medium power. References 11, figures 4, tables 2.

Global cryogenic Paschen test of the JT-60SA magnet system

Superconducting fusion magnets feature large inductances, and operate at high currents and at cryogenic temperatures. In case of a quench, the stored electromagnetic energy need to be immediately discharged, thereby inducing high voltages. High quality electrical insulation withstanding cryogenic temperatures is therefore essential for the safe operation of the magnet system. Local and integral Paschen tests at ambient temperature have become a standard to validate the electrical insulation of electromagnetic components of fusion devices. In order to mitigate the risk from a degradation of the electric insulation during cool-down, a global Paschen test of the complete magnet system at cryogenic temperatures is suggested. This paper focuses on the specific design of JT-60SA fusion device, analyses the boundary conditions for a cryogenic global Paschen test, and demonstrates its feasibility at limited risk during a future cooldown.

ASSESSMENT OF THE ADEQUACY OF COMPUTER SIMULATION OF THE ELECTROMAGNETIC ENVIRONMENT USING FREE SOFTWARE

Computer simulation of the electromagnetic environment makes it possible to determine the sources of the electromagnetic field and radiation at the object under study, accelerates the process of determining the degree of danger of the electromagnetic environment, forms pictures of the distribution in space of the components of the electromagnetic field and creates maps of the permissible time of human stay. Free software (openEMS, MEEP) significantly simplifies the solution of these tasks. The article considers the issues of assessing the adequacy of computer models of the distribution of electromagnetic field components formed using these modeling packages. The results of experimental measurements and computer simulation of the electric field at frequencies of 50 Hz, 30 kHz, 3 MHz, 30 MHz and 50 MHz are presented. The results of measurements and computer simulation of the electromagnetic field at frequencies of 800 MHz, 25 Khz and 40 GHz are presented. The adequacy of modeling the components of the electromagnetic field using openEMS and MEEP, sufficient for practical application, has been confirmed.

Marine controlled source electromagnetic data denoising while weak signal preserving based on jointly sparse model and dictionary learning

The amplitude of the marine controlled source electromagnetic (CSEM) signal decays dramatically with the augment of offset. The signal is easily contaminated by surrounding noise when the transmitter-receiver offset is large. Denoising is crucial for marine CSEM data processing and interpretation. Nowadays, most denoising methods focus on suppressing the noise influences for a single component. The inherent relations among different electromagnetic (EM) components are neglected. Besides, some weak signals are removed mistakenly to get a better denoising effect. In this paper, a new denoising method is proposed based on a jointly sparse model and dictionary learning, which utilizes the correlations among multi-components of marine CSEM data. Synthetic experiments prove that it can not only effectively remove noise, but also successfully protect weak signals. Field data application further validates the effectiveness of the proposed method.

Estimation of Stator Vibration in DFIM Under Various Types of Rotor Excitation

Variable speed power generation using Doubly Fed Induction Machine requires an adjustable frequency supply at the rotor terminals which can be achieved using power converters. Ideally, a variable frequency sinusoidal voltage should be applied, but it is not possible without the help of power converters. For a typical 250 MW DFIM with a speed variation of -10.73% to +8.33%, excitation power of 25 MW at 3.3kV and 11600 Amps is required. With this much high rotor current at low fundamental rotor frequency (3.75 Hz) electromagnetic forces in the air gap contain harmonic force components. Also, any time harmonic of radial force density in the rotor will be induced in the stator as a distinct time harmonic, modified by the influence of space harmonics in DFIM with regular three phase integral slot winding on both stator and rotor and vice versa. So, if the frequency and order of electromagnetic force components conflicts with mode shape and natural frequencies of the machine stator strong magnification in vibration will occur or more severely develops mechanical resonance. The stator vibration of electrical machine is generated by the electromagnetic forces acting on the surface of the stator tooths. This paper analyzes stator vibration for 250 MW DFIM in multiphysics simulation with its rotor winding excited through pure sinusoidal excitation at fundamental rotor frequency of 3.75 Hz and with two-Level voltage source converter at 3.75 Hz fundamental rotor frequency. Hardware results with supported multiphysics simulation on a laboratory prototype of 2.2 kW rating DFIM.

Design and manufacturing of waveguide of parabolic antenna using EDM process

Wireless technology was one of the main areas of research in the world of communication system today and a study of communication incomplete without an understanding of the operation and manufacturing of waveguide of parabolic antenna. Waveguide is an important electromagnetic wave transmission Component of parabolic antenna. potential benefits of parabolic antenna doesn’t required any cables to transmitte electromagnetic signal. Designing of waveguide was a most important role before its manufacturing. An attempt is made to design and manufacture the waveguide by varying cross- section using CREO software. Manufacturing of waveguide Carried out by milling, the inner pocket of waveguide was machined by Electrical discharge machining process. Which results accurate surface and suitable for travelling of electromagnetic wave without any disturbance.

Precipitation-related increase events of the electromagnetic component of secondary cosmic rays: Spectral analysis

We report the measurement results of differential spectra of electromagnetic radiation in the range 0.1–4 MeV, which occurs in the atmosphere as a component of secondary cosmic rays. Spectral monitoring was performed using a spectrometer based on the Nai (TL) crystal in 2022–2023. The main purpose of the measurements was to determine spectral characteristics of the electromagnetic radiation during increase events, when the electromagnetic radiation flux from the atmosphere rises by tens of percent with respect to the background level. From a thorough analysis of the spectra of many dozens of events, we have drawn a conclusion that although the lines of natural radionuclides are present on the spectra and contribute their share, their total contribution to the increase events is ~0.1 of the total energy supplied during an increase. We unambiguously conclude that the effect of increasing electromagnetic radiation during precipitation is not due to the presence of radionuclides in precipitation.

ЕЛЕКТРОМАГНІТНІ МОМЕНТИ УПРАВЛІННЯ ПРЕЦЕСІЙНИМ РУХОМ ТРИСТУПЕНЕВОЇ ЕЛЕКТРИЧНОЇ МАШИНИ

The main known structures and principles of functioning of electric machines with three degrees of freedom of rotational motion of the rotor are considered. The type of such machines in which it is possible to realize a high frequency of the rotor rotation is highlighted, which gives it the property of gyro-stabilization. The structure of the magnetic system of the machine of this type is presented and a hypothesis is put forward about the adequacy of the expressions of the classical analytical mathematical model, but the need for accurate calculation of the concentrated parameters that make up it. The distribution of magnetic flux density is analyzed based on a numerical mathematical model of a three-dimensional mag-netic field. The dependences of electromagnetic torque components and flux linkages on the rotor axis orientation and the angle of its rotation are calculated. It was concluded that the classical analytical mathematical model are adequate pro-vided that the calculating of its coefficients is based on the results of the modeling of three-dimensional magnetic field in the machine active volume and the surrounding space. It is underlined that, the amplitude of the flux linkage vector of the control winding and the fluctuations of the vector components to use in lumped parameter model must be calculated from the corresponding values of the electromagnetic torque components. Taking into account the results of the analysis of the three-dimensional field demonstrates a significant decrease in the speed of controlled precession and an increase in the amplitude of nutation. References 9, figures 10, tables 2.