Depth Estimation of a Buried Conductive Sphere as a Model of Unexploded
Ordnance Using Electromagnetic Induction Data
مجتبی
بابایی
دانشگاه آزاد اسلامی واحد تویسرکان
author
text
article
2015
per
In this paper, a novel scheme for depth estimation of a buried conductive sphere as a metallic mine using electromagnetic induction (EMI) data is presented. In electromagnetic induction method, the transmitter coil produces the incident magnetic and electric fields that obey the Maxwell’s equations. In the receiver coil, the received response is created in two modes. Eddy-current mode (ecV) is derived from the perfect conductor placed in the shallow depth and another mode called current-channeling response (ccV) which depends on the conductivity of the medium. As expected, these responses differ depending on the direction of the incident field related to the receiver coil’s axis. There is a case that the transmitter coil’s axis is parallel to the ground surface and only the eddy current response is measured in the receiver coil. By defining the maximum value of , ecV,the problem with depth determination transformed into the problem with finding a solution for a nonlinear equation of the form 0 z f.The method is applied to synthetic data with and without random errors. In all of the cases examined, the maximum error in depth is less than 6%.
Applied Electromagnetics
Imam Hussein University
2645-5153
3
v.
2
no.
2015
1
6
https://elemag.ihu.ac.ir/article_203351_0d79b8a61376de72e2b9d80e897b652e.pdf
Digital Beamforming Antenna Array to Unknown
Interference Countermeasure
سیدحسن
صدیقی
دانشگاه علم و صنعت ایران
author
ملیحه
رسولی امیرحاجلو
دانشگاه علم و صنعت ایران
author
text
article
2015
per
An optimal beam forming method is proposed which incorporates all electromagnetic characteristics of the antenna elements, including radiation pattern, mutual coupling and radome effect. The optimal beam forming technique minimizes the total power radiated by the antenna array while the response in a desired direction is maintained. By considering the active element patterns efficient beam forming algorithm is obtained which is able to manage all mutual coupling effects. Simulation results show the performance of the proposed algorithm applied to an antenna array.
Applied Electromagnetics
Imam Hussein University
2645-5153
3
v.
2
no.
2015
7
14
https://elemag.ihu.ac.ir/article_203352_e84013255f1e6c1ffb745e0cc9a40a9f.pdf
Starting Performance Improvement of Line Start PMSM by
Reduction of Space Harmonics
حمیدرضا
بهبهانی فرد
دانشگاه صنعتی مالک اشتر
author
علیرضا
صدوقی
دانشگاه صنعتی مالک اشتر
author
همایون
مشگین کلک
دانشگاه تفرش
author
text
article
2015
per
Line start permanent magnet synchronous motors possess many attractive features including high efficiency, low loss, high power factor, small volume and light weight. Also they need no inverter for starting which is economical for many single speed applications such as most fans, pumps and compressors. Therefore LSPMS motors have been considered as an alternative for induction motors, but the starting performance of LSPMS motors have been a challenging issue concerned by many researchers so far. Compared to Induction motors, because of braking torque due to permanent magnets, the winding space harmonics and their negative impacts on LSPMS motors torque characteristics should be considered more serious. In this paper, first the mmf distribution of stator winding in the air gap is studied based on Fourier analysis. Then by using an optimization process, a new stator winding has been developed, which has a lower harmonic content in its mmf than the conventional winding. Finally the method is applied to an existing LSPMS motor and its performance is obtained by a finite element analysis.
Applied Electromagnetics
Imam Hussein University
2645-5153
3
v.
2
no.
2015
15
24
https://elemag.ihu.ac.ir/article_203353_826746e3bb657f42bdfb98c9d56efff1.pdf
Analytical Design of On load Magnetic Flux Density and Flux-linkage in Radial Flux Air-cored Permanent Magnet Electrical Machine with a Double-sided Rotor
محمد رضا
علیزاده پهلوانی
دانشگاه مالک اشتر
author
بهروز
شیرالی
دانشگاه آزاد اسلامی واحد بروجردمحل کار نیروگاه شهید مدحج اهواز
author
text
article
2015
per
- This Articlea radial magnetic flux density and flux-linkage of the redial flux Air-Cored permanent magnet electrical machine (RFAMP) with double-sided rotor can be calculated analytically using the subdomain analysis is provided. First, Analytical relationships of on load magnetic flux density and flux-linkage of this machine are presented with of poisson equations and, then, these relationships are validated by finite element numerical results in Maxwell 16.02 software. Comparison show that difference between fundamental component of radial magnetic flux density and flux-linkage of analytical relations and that of finite element results is less than 3%. Also, It is shown that in this machine type appeared even harmonics, the radial component of the magnetic flux density is not symmetrical, unit half cycle and Lack of attention to this subject in design of the machine can cause be inner or outer yoke magnetic saturation. In this article to calculate the flux linkage resulting from of the armature reaction all the components of winding conductor density distribution as well as in the calculation the flux linkage all radial components of the magnetic flux density is used. The relevant authorities of this research is only the first radial component of the magnetic flux density and the second component winding conductor used And the other component is ignored. It is shown that this topic compared with the relevant authorities 21% increase in flux linkage or inductance RFAPM machine that the number are significant in the study of magnetic saturation yokes. Worth noting that the study of the comparative results, only up to 17th harmonics and taking into account the higher harmonics can adapt better to have the finite element results
Applied Electromagnetics
Imam Hussein University
2645-5153
3
v.
2
no.
2015
25
34
https://elemag.ihu.ac.ir/article_203354_2ee25c8b6c974861066c4ddc3acc306e.pdf
Transient Analysis of Single-Conductor Overhead Lines Terminated to
Grounded Arrester Considering Frequency Dependence of Electrical
Parameters of Soil using Genetic Algorithm
حمید
یزدی
دانشگاه اراک
author
سعید رضا
استادزاده
دانشگاه اراک
author
فرزین
طاهری آستانه
دانشگاه اراک
author
text
article
2015
per
In this paper, a genetic algorithm-based approach for transient analysis of single-conductor overhead line connected to grounded arrester is proposed. In analysis, the grounding systems are buried in lossy dispersive soil, i.e., the electrical parameters of soil are frequency-dependent. In dealing with the problem, the lightning current pulse is first approximated by a finite set of sinusoidal harmonies in a time domain. Norton equivalent circuit viewed across the arrester is then computed via transmission line model (TLM). Finally analyzing this nonlinear circuit by genetic algorithm, transient voltage across the arrester is easily computed. Comparison of the achieved transient voltages with and without considering dispersion of soil shows that this effect plays an important role in selecting lightning arresters and the insulation coordination study of power systems. Moreover, in comparison with arithmetic operator method (AOM), the run-time is reduced.
Applied Electromagnetics
Imam Hussein University
2645-5153
3
v.
2
no.
2015
35
42
https://elemag.ihu.ac.ir/article_203355_1f75b9a53ae5bf8b779b68957a501d30.pdf
Modeling and Calculation of Coupling Between Antenna on Aircraft by
Calculation of Geodesic
سیدمحمدجواد
رضوی
مالک اشتر
author
ناصر
یوسف زاده
دانشگاه مالک اشتر- ارشد/امام حسین ورودی امسال دکترای جنگ الکترونیک
author
سیدحسین
محسنی ارمکی
دانشیار و هیات علمی دانشگاه صنعتی مالک اشتر تهران
author
text
article
2015
per
Antennas that are installed on the aircraft, must have minimum mutual coupling so that the function of the transmitter and receiver will not be interfered. For coupling calculation, we must obtain wave pass from transmitter antenna to receiver antenna. In case that antennas are LOS, this pass is a direct pass. But in case that antennas are NLOS, a kind of surface wave causes mutual coupling. The best way for calculation of coupling is through obtaining geodesics. Then by calculation of surface loss, we can get the amount of coupling. if the aircraft is modeled with a cylinder, calculation of geodesics is easy and practical. the advantage of this approximation is that we can extend it for any aircrafts with cylindrical fuselages. in this approximation, the effect of obstacles and diffraction in edges is not considered. in this paper, results of mutual coupling calculation, results of simulation as well as the measured data is compared in approximated model of the aircraft. It will finally be shown that in the worst case, calculation results are not greater than 15db.
Applied Electromagnetics
Imam Hussein University
2645-5153
3
v.
2
no.
2015
43
54
https://elemag.ihu.ac.ir/article_203356_ebace74f8a80a637cdf459f4b7ec4503.pdf