• 한국정보통신학회논문지
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• 제14권5호
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• pp.1085-1092
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• 2010

본 논문에서는 최적화 알고리즘인 PSO를 이용하여 한국인의 생활자계 노출실태 조사 시 확보한 16세 이하의 미취학 아동, 초등학생, 중학생 실측 데이터베이스를 활용하여, 자계노출의 정도를 실측에 의하지 않고 추정할 수 있는 '24시간 소아고노출 생활자계 추정식'을 개발하였다. 24시간 개인자계 노출량 추정식의 입력 데이터는 성, 연령, 주거형태, 주거지 크기, 선로이격거리 및 송전전압을 사용하였다. 그리고 16세 이하에 대해서 24시간 고노출 개인자계 노출분포, 자계노출의 특성, 특정 조건별 자계노출특성 등을 분석하였다.

• Journal of Electrical Engineering and Technology
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• 제13권4호
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• pp.1586-1595
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• 2018

For the problem that the complexity of 3-D modeling and multi parameter optimization, as well as the uncertainty of the winding factor of axial flux permanent magnet generator with coreless windings. The complex 3-D model was simplified into 2-D analytic model, and an analytical formula for the winding factor that adapting different coreless stator winding is proposed in this paper. The analytical solution for air-gap magnetic fields, no-load back EMF, electromagnetic torque, and efficiency are calculated by using this method. The multiple objective and multivariable optimization of the maximum fundamental and the minimum harmonic content of back EMF are performed by using response surface methodology. The proposed optimum design method was applied to make a generator. The generator was tested and the calculated results are compared with the proposed method, which show good agreements.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.25-27
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• 2005

This paper deals with the comparison and analysis of brushless DC (BLDC) motor with radial and polar anisotropic plastic magnet. The open-circuit field distributions and back-emf for BLDC motor with polar plastic magnet are established analytically and the results are validated extensively by comparison with finite element (FE) analyses. On the basis of two dimensional (2-D) analytical solutions, this paper predicts open-circuit field characteristics according to design parameters and makes a comparison between BLDC motor with polar plastic magnet and it with radial plastic magnet in terms of required magnet volume and harmonic of air-gap flux density waveform.

• 한국전자파학회논문지
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• 제18권8호
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• pp.977-983
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• 2007

최근 근거리에서 수신 모듈에 무선으로 전력을 전달하는 시스템이 많아지고 있다. 무선으로 전력을 공급할 때, 수신 공간의 효율적인 사용을 위하여 ferrite core 주변에 코일을 감아 유도기 전력을 얻는다. 본 논문에서는 100kHz 균일한 단방향의 자계 환경 내에 위치한 페라이트 코어 내부의 자계 분포를 분석한다. 수치 분석을 위 한 시뮬레이터는 유한요소 기법을 적용한 Ansoft사의 Maxwell Tool을 사용하였다. 페라이트 코어의 비투자율의 변화에 따라 집속되는 자속 밀도의 변화를 알아보고, 코일의 권선을 위해 코어의 일부를 잘라내었을 시 총자속의 변화량을 알아보았다. 계산 결과, 100 kHz 자계 환경 내에서 작은 페라이트 코어를 이용하면 코어 내에 약 $3.5{\sim}4$배의 자속 밀도가 증강됨을 확인하였다. 비투자율이 800이면서 반지름의 길이가 4.75 mm인 페라이트 코어의 가장자리에 0.5mm를 도려내었을 때 총 자속은 23% 감소함을 확인하였다.

• 한국산업보건학회지
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• 제32권4호
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• pp.381-392
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• 2022

Objectives: Objective of this study is to review briefly exposure characteristics, monitoring instruments and threshold limit values for extremely low frequency-magnetic field (ELF-MF) methods. This study was undertaken through brief literature review. We performed a literature search in PubMed to identify ELF-MF studies conducted in workplaces. Initial search keywords such as 'extremely low frequency-magnetic field (ELF-MF)' and 'electromagnetic fields (EMF)' combined or singly. We limited our review to occupational rather than general nonworkplace environmental exposures. Methods: The contents we reviewed: key industry and occupations generating ELF-MF, several direct-reading instruments monitoring ELF-MF and threshold limit values (TLV) preventing health effects may be caused by the exposure to ELF-MF. Results: The industries related to the generation and supply of electricity, electrolytic installations, welding, and induction heating and more were regarded as high ELF-MF exposure industries. All jobs handling or employed performed in power cable lines, electrical wiring, and electrical equipment are found to be exposed to ELF-MF. Threshold or ceiling limit, 1,000 µT, is established to prevent acute effects of exposure to low-frequency EMFs on the nervous system: the direct stimulation of nerve and muscle tissues and the induction of retinal phosphenes. The International Agency for Research on Cancer (IARC) has classified ELF-MF as possibly carcinogenic to humans chiefly based on epidemiological studies on childhood leukemia. However, a causal relationship between magnetic fields and several types of cancer including childhood leukemia has not been established nor has any other long-term effects. Risk management using precautionary measures, has been initiated by the US and EU to prevent chronic health effects related to ELF-MF exposure in workplaces. Conclusion: This study recommends the implementation of various measures such as theestablishment of occupational exposure limit values for ELF-MF and precautionary principle to prevent potential chronic occupational health effects may be caused by ELF-MF in Korea.

• 전기학회논문지
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• 제56권12호
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• pp.2135-2144
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• 2007

This paper presents system design of the slotless double-side Permanent Magnet Linear Synchronous Machine system (PMLSM) through magnetic field analysis and dynamic modeling. In our analysis, 2-D analytical treatments based on the magnetic vector potential were adopted to predict magnetic field with space harmonics by PM mover magnetization and stator winding current. From these, the design parameters such as inductance, Back-emf, and thrust are estimated. And, the electrical dynamic modeling including synchronous speed is completed by calculation of a DC link voltage in effort to obtain the accurate mechanical power from Space Vector Pulse Width Modulation(SVPWM). Therefore, the system design of PMLSM is performed from estimation of design parameters according to PM size and coil turns in magnetic field and from calculation of a DC link voltage to satisfy base speed and base thrust represented as the maximum output power in dynamic modeling. The estimated values from the analysis are verified by the finite element method and experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.89-91
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• 2008

This paper deals with the thrust calculations and the measurements of a cylindrical Linear Oscillatory Actuator (LOA) sing Transfer Relations Theorem (TRT), namely, Melcher's methodology. Using transfer relations derived in terms of a magnetic vector potential and a two-dimensional (2-d) cylindrical coordinate system, this paper derives analytical solutions for the magnetic vector potential, magnetic fields due to Permanent Magnets (PMs) and stator winding currents and the thrust. The analytical results are validated by non-linear Finite Element (FE) analyses. In particular, test results such as thrust and back-emf measurements are given to confirm the analysis.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2007년도 학술대회
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• pp.207-210
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• 2007

최근 전자파에 일반인에 대한 관심이 높아지고 있고, 기업들의 환경경영의 일환으로 전자파환경 관리도 하나의 이슈로 대두되고 있다. 초고속인터넷서비스 속도개선을 위해 통신장치를 기존의 전화국사내에서 가입자 주택 가까이 또는 주택 건물의 내부로 이동하여 설치하고 있다. 이런 경우 주변 거주자들은 전자파의 인체 유해성에 대한 우려를 하게 되며, 이로 인해 일부 장치설치 곤란하여 서비스제공에 어려움이 발생하기도 한다. 본 논문은 초고속서비스 제공을 위해 가입자 가까이에 설치된 여러 지역의 옥외 통신설비 주변에서 전자파 측정기술을 서술하고 측정된 결과를 국내 기준과 비교 분석하였다. 측정결과 국내 기준보다 매우 낮은 결과를 보였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.731-732
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• 2008

This paper deals with design and characteristics analysis of 7.5-kW, 60,000-rpm class permanent magnet synchronous motor for turbo compressor. In order to determine the design parameters of rotor, torque per rotor volume method is applied. And, to analyze the magnetic field distribution and estimate the electrical parameters such as back EMF constant, inductance and torque constant, electromagnetic transfer relations theorem is employed. We compare the characteristics analysis results of model designed by proposed method with those by nonlinear FEA. As a result of this, the design have been validated.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.1061-1063
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• 2004

This paper deals with the application of cylindrical Halbach array to a PM motor capable of producing pure rotary motion, pure linear motion, or helical motion, The proposed motor consists of an exterior polar Halbach array for a rotary motion and interior cylindrical Halbach array for a linear one. The two- dimensional space harmonic method is employed for predicting the electromagnetic characteristics, with reference to the following parameters as variables: magnetic field, torque/thrust and back emf.