• Title, Summary, Keyword: Electromagnetic aspects

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Simplified Modeling of Ring Resonators and Split Ring Resonators Using Magnetization

  • Jeon, Dongho;Lee, Bomson
    • Journal of electromagnetic engineering and science
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    • v.13 no.2
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    • pp.134-136
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    • 2013
  • This paper examines various aspects of the electromagnetic responses of the ring resonator located in the transverse electromagnetic cell. In addition, an equivalent circuit for the ring resonator is proposed and analyzed based on the electromagnetic phenomenon of the resonator. The equivalent circuit was simply modeled based on the concept of magnetization. A method for achieving a wider operating bandwidth of the negative permeability is provided. The ring resonator with its resonant frequency of 13.56 MHz was designed and its characteristics were examined in terms of S-parameters, effective permeability, loss rate, bandwidth, etc. The circuit and electromagnetic simulation results show an excellent agreement as well as that of theory.

Practical Design Considerations for Large PM Machines

  • Qu, Ronghai;Zhang, Xiaolong
    • Journal of international Conference on Electrical Machines and Systems
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    • v.3 no.1
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    • pp.72-77
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    • 2014
  • To help machine designers to make precise design of large permanent magnet (PM) machines, this paper presents a set of design considerations that are very often ignored by machine designers. These considerations are categorized into several aspects: electromagnetic (EM) performance, losses and efficiency, fault and stability, and some other issues. The effects of various practical factors are presented and some corresponding design methods are introduced.

Electromagnetic Characteristics Analysis of High-speed Brushless DC Motor (고속 BLDC 전동기의 전자기 특성 해석)

  • Park, Hyung-Il;Jang, Seok-Myeong;Choi, Jang-Young
    • Proceedings of the KIEE Conference
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    • pp.916-917
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    • 2015
  • This paper deals with electromagneitc characteristics analysis of high-speed brushless DC motor. First, under same rated and restricted conditions, four models which have different slot combinations each other are designed using 2-d finite element (FE) analyses. Designed models are analyzed and compared in terms of core loss, copper loss, eddy-current loss, etc. On the basis of analysis results, it is found that the motor with a 2-pole PM rotor and a 6-slot stator has most outstanding performances in electromagnetic aspects.

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Aspects on Nonuniqueness and Instability Inherent in Inverse Scattering Problems

  • Kim, Se-Yun
    • Journal of electromagnetic engineering and science
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    • v.3 no.2
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    • pp.133-139
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    • 2003
  • The nonuniqueness of a mathematically rigorous solution to 2-dimensional inverse scattering problems is explained in a limiting view of the numerical calculations based on the spectral-domain moment method. It is illustrated that its theoretical uniqueness cannot be assured even by performing additional measurements of the scattered fields not only along multiple lines but also with angular/frequency-diversities. In a real situation, however, computational error and measurement noise are inevitable. Those limitations render it meaningless to controvert the existence of a theoretically rigorous solution. Hence the most practical issue is how to remedy the instability of its practically approximate solution.

Development of a 3.5 mm Coaxial Microcalorimeter for Microwave Power Standards (3.5 mm 동축형 미소열량계 개발과 전자파전력 측정표준 확립)

  • Kwon, Jae-Yong;Kim, Jeong-Hwan;Kang, Tae-Weon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.9
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    • pp.989-996
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    • 2009
  • RF and microwave power is a basic quantity in electromagnetic metrology which linked directly to major electro-magnetic quantities such as attenuation, RF voltage, antenna characteristics and field strength. This paper deals with a power meter and power sensor with associated theory for RF and microwave power measurement. We study the theory and the key aspects in design of a 3.5 mm coaxial microcalorimeter which works from 50 MHz to 26.5 GHz as a primary microwave power standard.

Design and Analyses of Vibration Driven Electromagnetic Energy Harvester with High Power Generation at Low Frequency (저주파수 진동형 전자기식 마이크로 발전기의 설계 및 해석)

  • Lee, Byung-Chul;Chung, Gwiy-Sang
    • Journal of Sensor Science and Technology
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    • v.20 no.2
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    • pp.102-106
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    • 2011
  • This paper presents a design and analysis of an electromagnetic micro generator which can convert low frequency vibration energy to electrical power. The design aspects of the micro generator comprised planar spring, Cu coil and a permanent magnet(NdFeB). Threetype spring designs and four materials(Parylene, FR-4, Cu and Si) were compared to find resonance frequency. It was found that the resonance frequency will be changed according to the spring shape and material. Mechanical and magnetic parameters had been adjusted to optimize the output power through a comprehensive theoretical study.

Design and Analysis of Surface-Mounted PM Motor of Compressor for Electric Vehicles Applications according to Slot/Pole Combinations (전기자동차 압축기용 표면부착형 영구자석 전동기의 극/슬롯수 조합에 따른 특성해석 및 설계)

  • Choi, Jang-Young;Park, Hyung-Il;Jang, Seok-Myeong;Lee, Sung-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.10
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    • pp.1846-1857
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    • 2011
  • This paper deals with design and analysis of surface-mounted PM (SPM) motor for compressor of air-conditioning system for electric vehicle applications according to slot/pole combination. First, required torque-speed curve characteristics are determined from operating conditions of the compressor. Restricted conditions such as motor size limit and current density are also determined. And then, under same rated and restricted conditions, twelve models which have different slot/pole combinations each other are designed for various pole arc/pitch ratio using simple equations and 2-d finite element (FE) analyses. Designed models are analyzed and compared in terms of back-emf THD, cogging torque, torque ripple, power losses, efficiency, etc. On the basis of analysis results, it is found that the motor with a 6-pole PM rotor and a 27-slot stator has most outstanding performances in electromagnetic aspects. Finally, through the mechanical modal analysis and demagnetization analysis, it is concluded that the determined motor is most suitable for the compressor of air-conditioning system for electric vehicles.

An Experimental Study on the Characteristics of Electromagnetic Filter (전자기 필터의 특성에 관한 실험적 연구)

  • Lee, Geum-Yong;Lim, Seung-Cheol;Lee, Kun-Jai
    • Nuclear Engineering and Technology
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    • v.25 no.1
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    • pp.178-191
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    • 1993
  • The electromagnetic filter has been recognized as a technological replacement for the conventional filtration systems of the nuclear power plant coolant. But, as of now there are neither clear understandings of the phenomena occurring in the electromagnetic filter nor the general theoretical analyses. These facts make the application or the electromagnetic filter to the real systems a little risky, and therefore it has not been commercialized although it shows excellent performances in such situations as the plant abnormality, where the conventional filters usually fail. This experimental study of the low power electromagnetic filter aims at the clarification of the general characteristics under varying operational parameters. Since the detailed characteristics may differ from one electromagnetic filter to another, they are considered secondary. The impurities applied are the highly magnetic magnetite (Fe$_3$O$_4$) and the diamagnetic cuprous oxide (Cu$_2$O). The empirical equations are derived from the experimental data by the regressional analyses. They are classified of three types : Efficiencies vs. Time, Efficiencies vs. Load, and Load vs. Time. The characteristics of the electromagnetic filter observed in this experiment agreed well with other related works in many aspects. Especially in this study, some assumptions and discussions including the physical deposition are combined for the explanations of the filter characteristics found in our and other experimental works.

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Air Gap Responses of the Maglev Vehicle UTM-01 to Irregularities of Guideway (자기부상열차 UTM-01의 부상 공극 해석)

  • Han, Hyung-Suk;Kim, Sook-Hee;Yim, Bong-Hyuk;Kwon, Jung-Il;Hur, Young-Chul
    • Proceedings of the KSR Conference
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    • pp.291-295
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    • 2007
  • The irregularities in the guideways used in the Maglev transportation system that result from surface roughness and deflection of guideway have strong effects on the dynamic characteristics of Maglev vehicles, because the electromagnetic suspension of Maglev vehicles strongly interacts with the guideway. For this reason, a numerical prediction of air gap responses to these irregularities is desirable to improve aspects of running performance, such as stability and passenger comfort, while minimizing aesthetic impact and construction cost. This paper presents a procedure to predict the air gap response which is a criteria for stability, and investigates the responses with the goal of attaining higher travel speeds in the urban Maglev vehicle UTM-01 utilizing electromagnetic suspension.

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Performance of Spiked Population Models for Spectrum Sensing

  • Le, Tan-Thanh;Kong, Hyung-Yun
    • Journal of electromagnetic engineering and science
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    • v.12 no.3
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    • pp.203-209
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    • 2012
  • In order to improve sensing performance when the noise variance is not known, this paper considers a so-called blind spectrum sensing technique that is based on eigenvalue models. In this paper, we employed the spiked population models in order to identify the miss detection probability. At first, we try to estimate the unknown noise variance based on the blind measurements at a secondary location. We then investigate the performance of detection, in terms of both theoretical and empirical aspects, after applying this estimated noise variance result. In addition, we study the effects of the number of SUs and the number of samples on the spectrum sensing performance.