• 한국자기학회지
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• 제19권6호
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• pp.222-226
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• 2009

기존의 평판형 전자기 엑츄에이터에 쇼티드 턴을 적용한 새로운 형태의 평판형 전자기 엑츄에이터를 제안하였다. 기존의 평판형 전자기 엑츄에이터에서 발생하는 인덕턴스에 의한 초기응답 지연현상을 줄이기 위해 본 논문에서는 기존의 엑츄에이터의 요크와 요크 사이에 중간요크(center yoke)를 추가하고, 쇼티드 턴을 적용한 새로운 형태의 평판형 전자기 엑츄에이터를 제안 하고, 상용 자기장 해석 프로그램인 MAXWELL을 이용한 시뮬레이션을 통해 동적 성능 향상을 검증 하였다.

• 한국전기전자재료학회논문지
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• 제17권4호
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• pp.460-464
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• 2004

In recent, there have been several developments in lamp technology that promise savings in electrical power consumption and improved quality of the lighting space. Above all, the advantage of ring-shaped electrodeless fluorescent lamp is the removal of internal electrodes and heating filaments that are a light-limiting factor of conventional fluorescent lamps. Therefore, the life time of ring-shaped electrodeless fluorescent lamps is substantially higher than that of conventional fluorescent lamps and last up to 60,000 hours and is intended as a high efficacy replacement for the incandescent reflector lamp in many applications. In this paper, maxwell 3D finite element analysis program (Ansoft) was used to obtain electromagnetic properties associated with the coil and nearby structures. The electromagnetic emitting properties were presented by D simulation software operated at 250KHz and some specific conditions. Photometric characteristic of the ring-shaped electrodeless fluorescent lamp were investigated using LS-100 lightmeter and TA-0510 thermometer respectively.

• 비파괴검사학회지
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• 제23권6호
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• pp.622-634
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• 2003

This paper is concerned with a computational method for recovering a crack shape of steam generator tubes of nuclear plants. Problems on the shape identification are discussed arising in the characterization of a structural defect in a conductor using data of eddy current inspection. A surface defect on the generator tube ran be detected as a probe impedance trajectory by scanning a pancake type coil. First, a mathematical model of the inspection process is derived from the Maxwell's equation. Second, the input and output relation is given by the approximate model by virtue of the hybrid use of the finite element and boundary element method. In that model, the crack shape is characterized by the unknown coefficients of the B-spline function which approximates the crack shape geometry. Finally, a parameter estimation technique is proposed for recovering the crack shape using data from the probe coil. The computational experiments were successfully tested with the laboratory data.

• 한국진공학회지
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• 제8권3B호
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• pp.368-375
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• 1999

The Maxwell equation and the transformer equivalent-circuit model are applied to a radio frequency planar inductively coupled plasma. The spatial distribution of the vector potential, the magnetic field, and the electric field are obtained analytically. As a result, the plasma current, the mutual inductance between the coil and the plasma, and the self inductance of plasma are found to increase with increasing skin depth. The spatial distribution of absorbed power has maximum where the antenna coil exists, and has a similar profile to that of the induced electric field. The power transfer efficiency is found to increase with increasing gas pressure before a saturation around p+ 20mTorr, while it shows an increase with the plasma density before a slight decrease around a density of $5\times10^{11}/\textrm{cm}^3$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.132-134
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• 2001

In this paper, by designning the width of the stator coil, double sided excitation LDM with multi-separated winding which is possible to obtain the constant thrust force is proposed. Using Maxwell 2D, Empulse, we were proved the characteristic analysis of LDM accoding to ratio magnet width venus coil width of LDM. Though designning for double sided excitation LDM with multi-separated winding, we could be achieved the constant thrust and rapidly time responses within the operating region.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 B
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• pp.290-293
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• 2000

In this paper, by designing the width of the stator coil, double sided excitation LDM with multi-separated winding which is possible to obtain the constant thrust force is proposed. Using Permeance method, equvalent magnetic circuit method, Maxwell 2D, which is the magnetic field analysis package, we were analyzed and proved the validity of design process, also the characteristics of LDM according to magnet vs. coil width ratio of LDM was almost in accord with the experiment results.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.785-788
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• 2005

In this study, micro-scale, high-performance, solenoid-type RF chip inductors were investigated. The size of the RF chip inductors fabricated in this work was $1.0{\times}0.5{\times}0.5mm^3$ The material and shape of the core were 96% $Al_2O_3$ and I-type. The material and number of turn of coil were copper (Cu) and 6. The diameter ($40{\mu}m$) of coil and length (0.35mm) of solenoid were determined by a Maxwell three-dimensional field simulator to maximize the performance of the inductors. High frequency characteristics of the inductance (L) and quality-factor (Q) of developed inductors were measured using an RF Impedance/Material Analyzer (HP4291B with HP16193A test fixture). The inductors developed have inductances of 10.8nH and quality factors of 25.2 at 250MHz, and show results comparable to those measured for the inductors prepared by CoilCraftTm that is one of the best chip inductor company in the world. The simulated data predicted the high-frequency data of the Land Q of the inductors developed well.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권12호
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• pp.592-600
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• 2005

In this paper, a low loss magnetic levitation(Maglev) system is suggested and tested. The suggested Maglev system includes four hybrid magnets which consist of permanent magnet and coil. In the steady state, the levitated module system can be supported by attraction force generated by permanent magnet. The coil current controls only dynamic loads due to external disturbances. The module systems are designed by using finite element method(FEM) software tools such as MAXWELL and ANSYS. Also, digital control systems are designed to keep the magnet airgap at a constant value. The control systems include a VME(versa module europa)-based CPU(central processing unit) board, AD(analog to digital) board, PWM(pulse width modulation) board, 4-quadrant chopper, and sensors. In order to estimate the vertical velocity of the magnet, we use second order state observer with acceleration and gap signals as input and output signals, respectively. The characteristics of the suggested low loss Maglev system are demonstrated by experimental results showing coil current of 0A in the steady state of 3m airgap and performance specifications are satisfied for reference gap and force disturbance.

• 한국전기전자재료학회논문지
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• 제17권5호
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• pp.552-559
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• 2004

In recent, there have been several developments in lamp technology that promise savings in electrical power consumption and improved quality of the lighting space. Above all, the advantage of ring-shaped electrodeless fluorescent lamp is the removal of internal electrodes and heating filaments that are a light-limiting factor of conventional fluorescent lamps. The ring-shaped electrodeless lamp is intended as a high efficiency replacement for the incandescent reflector lamp in many applications. Therefore, the life time of ring-shaped electrodeless fluorescent lamps is substantially higher than that of conventional fluorescent lamps and last up to 60,000 hours. In this paper, maxwell 3D finite element analysis program(Ansoft) was used to obtain electromagnetic properties associated with the coil and nearby structures. The electromagnetic emitting properties were presented by 3D simulation software operated at 250 KHz and some specific conditions. The optical characteristics were measured luminance and a temperature and an optical spectrum distribution for 10 min in a one minute interval at the same time. With a goal of finding alternative materials, we show measurement results of electrical characteristics of a ring-shaped electrodeless fluorescent lamp as a function of frequency and the number of coil turns using a highly permeable($\mu$$_{r}$(equation omitted) 2,000) Mn-Zn ferrite. These results are compared with those of conventional ring-shaped electrodeless fluorescent lamp. It is found that the resistance, inductance and impedance are increased while the quality factor decreases as frequency increases.s.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권6호
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• pp.255-261
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• 2005

Recently, the RF inductive discharge or inductively coupled plasma continues to attract growing attention as an effective plasma source in many industrial applications, the best known of which are plasma processing and lighting technology. To the point of lighting sources, the ring-shaped electrodeless fluorescent lamps utilizing an inductively coupled plasma have been objects of interest and research during the last decades, mainly because of their potential for extremely long life, high lamp efficacies, rapid power switching response. In this paper, maxwell 3D finite element analysis program (Ansoft) was used to obtain electromagnetic properties associated with the coil and nearby structures. The electromagnetic emitting properties were presented by 3D simulation software operated at 250 kHz and some specific conditions. The electromagnetic field in the ferrite core was shown to be high and symmetric. An LS-100 luminance meter and a Darsa-2000 spectrum analyzer were used in the experiment. According to data on the lamp tested using high magnetic field ferrite, the optical and thermal wave fields were shown to be high around the ring-shaped electrodeless fluorescent lamp. The optical or light field was high at the center of the bulb rather than around the ferrite core. The light conditions of the bulb were assumed to be complex, depending on the condition of the filler gas, the volume of the bulb, and the frequency of the inverter. Our results have shown coupling between the gas plasma and the field of the light emitted to be nonlinear.