• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.851_852
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• 2009

Shrink fitting which is assembling process to fix stator core on the motor frame is widely used at the mass production line of motors because of cost and productivity. This process produces compressive stress on a stator core, which causes negative effect for example, core and copper losses on motor performance. Magnetic properties of electrical steel are effected by both compressive and tensile and thermal stresses. Electromagnetic field analysis is considered one of the effective process since one can predict motor performance including core loss precisely. This method can consider non linear magnetic property with magnetic saturation which is typical electrical steel behavior. However this method is strongly depended on non linear magnetic data, one may have different calculation result whether considering mechanical stress or not. This study describes magnetic field analysis of a motor considering mechanical stress from shrink fitting. Analysis results are compared with each stress-free and stressed condition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.76-76
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• 2008

갈륨-질화물(GaN) 기반의 고속전자이동도 트랜지스터(high electron mobility transistor, HEMT)는 최근 마이크로파 또는 밀리미터파 등의 고주파 대역의 통신시스템에 널리 사용되는 전자소자이자, 차세대 고주파용 전력 소자로 각광받고 있다. AlGaN/GaN HEMT에서 AlGaN층과 GaN층의 이종접합 구조(heterostructure)는 두 물질 간의 큰 전도대의 불연속성으로 인해 발생하는 이차원 전자가스(two-dimensional electron gas, 2DEG) 채널을 이용하여 높은 전자이동도, 높은 항복전압 및 우수한 고출력 특성을 얻는 것이 가능하다. 그러나 이린 이론적인 우수한 특성에도 불구하고 실제 AlGaN/GaN HEMT 소자에서는 AlGaN 표면과 AlGaN과 GaN 층 사이 접합면, AlGaN과 GaN 벌크층에 존재하는 트랩의 영향으로 이론보다 낮은 DC 출력 특성을 갖는다. 본 논문에서는 표면, 접합면, 벌크 층에 존재하는 트랩들을 각각의 존재 유무에 따라 시뮬레이션 함으로써 각각의 트랩이 DC 특성에 미치는 영향에 대해서 알아본다. 또한 소스와 게이트, 드레인과 게이트간의 거리에 따라 표면 트랩에 따른 영향과 AlGaN층과 GaN 층의 두께를 변화시켜가면서 각 층의 두께에 따라 벌크 트랩이 DC 특성에 미치는 영향을 알아보았다. 본 논문에서 트랩에 따른 특성의 파악을 위해서 $ATLAS^{TM}$를 이용하여 전산모사 하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.10
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• pp.35-39
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• 2007

Home appliances, like air-conditionals, washers, refrigerators, etc., can cause voltage fluctuations and light flicker. A standardized flicker test has been established in Europe(IEC 61000-3-3, IEC 61000-3-11). The supply impedance of power supply system varies from plate to place, and for the flicker test in KOREA, the appliance manufacturers do need standardized impedance like the one indicated in IEC 61000-3-3 for 230[V]/50[Hz]. Without it, the same appliance will have different flicker level at different places. For appliance manufacturers, the flicker limit should be related to the reference impedance. However, the European flicker test is designed for 230[V]/50[Hz] power and needs to be modified for a 1P2W(220[V]/60[Hz]) supply system in KOREA. In this paper, the reference impedance for KOREA(220[V]/60[Hz]) systems is proposed. The measured result provided in this paper was served as a proposal for establishing KOREA reference impedance for 220[V]/60[Hz] and has been published in IEC 60725.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.4
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• pp.139-143
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• 2006

Recently, standard of living improved and Information-Communication industry developed rapidly. Thereby, interest about electric power quality is rising worldwide. So, research and Development to enhance electric power quality in various viewpoint until most suitable supply system from each kind device to improve electric power quality. And specially, interest about voltage quality is rising by diffusion increase of information communication appliance and minuteness control appliance etc. Also Power consumption is increasing, but expansion of large size generator by environmental and site security problem is difficult. So, introduction of distribution generation is investigated actively by electric-power industry reorganization. Voltage management of power system had been controlled by ULTC (Under Load Tap Changer) in substation and pole transformer on the high voltage distribution line. But, voltage control device on substation and distribution line is applied each other separatively. Therefore, efficiency of line voltage control equipment is dropping. Also, research about introduction upper limit of distribution generation is consisting continuously. This paper presents cooperation use way between voltage control device and introduction upper limit of distribution generation for most suitable voltage control in distribution power system.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.159-162
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• 2003

In this paper, we present a middleware that using routing scheme that support easily for various type of network in a home network based heterogeneous network. The protocol presented in this paper, consist two layers that Network Adaptation Layer(NAL) to allow access varience networks and Network Interface Layer(NIL) to deal network dependent parts. The middleware presentedl in this paper, can easily send data to any digital appliance or receive data from any digital appliance by using our routing scheme.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.26-29
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• 2001

In this paper, a brief overview of problems related to the electromagnetic, mechanical design criteria is reported. Also, we described the results about the comparisons between BLDC motor and induction motor for Turbo Compressor considering motor cost, efficiency and reliability. As a result, we select an induction motor for 12.5RT Turbo compressor for the application of small building's all-conditioning system. Finally, a prototype induction motor was manufactured and tested under compressor set. The test results were successfully met the mechanical, thermal and electromagnetic point of view.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.861-864
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• 2006

냉장고에 적용된 BLDC Fan Motor에 있어서 공진소음의 원인에 대하여 연구하였다. 연구에 있어서 종래의 가진 방법을 적용하기 곤란한 구조를 가진 소형 Fan & Rotor System의 동 특성 실험에서 전자 가진법 및 Microphone을 이용한 고유진동수 계측방법을 사용하고 그 타당성을 보였으며 연구결과, Pan과 Rotor System의 비틀림 고유진동수와 Fan의 굽힘 고유진동수가 BLDC Motor의 Commutating Torque Ripple에 의한 가진 주파수와 일치하여 공진이 발생하는 것으로 분석 되었으며 이와 관련된 주요 인자를 분석하고 대안을 제시하였다.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.843-845
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• 2003

In this paper, the design of the outer core which is one part of the linear motor is investigated by using the topology optimization and FEM. The object functions are to reduce the outer core area of the linear motor with the maximum magnetic energy in airgap. For topology optimization, the finite element model is made through the result of ANSYS, and the sensitivity calculation is done using ANSTOP(developed general software for topology optimization of electromagnetics). In ANSTOP, the optimization routine is implemented using SLP in DOT and the ANSYS is used as a function solver.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.684-686
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• 2003

Until recently, the 2-D FEA neglects the magnetic field fringing and end-leakage, it leads to the approach of a trial and error experimental design. Since 3-D FEA is investigated for exact side force analysis of Linear Motor for Linear compressor. For the 3-B FEA, ANSYS as commercial tool are used.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.417-420
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• 2006

UPnP presents home network middleware for local home electrical appliances basedon internet protocols that is available access and control electrical appliances just in local home network. Itis designed to bring easy-to-use, flexible, standards-based connectivity to ad-hoc or unmanaged networks in the home, a small business, public spaces, or attached to the Internet. In this paper, Internet Gateway expands UPnP IGD(Internet Gateway Device) DCP(Device Control protocol) and UPnP IGP Bridge for Internet Home Network Electrical Appliance Control. UPnP IGD DCP is configurable initiation and sharing of internet connections, advanced connection-management features, management of host configuration service, and supports transparent Internet access by non-UPnP-certified devices. UPnP Bridge search for local home network devices by sending control messages. Control Point of UPnP Bridge search for devices of interest on the network and can control or be controlled all of functions by IGD DCP with control commands. Outside client, approach to UPnP IGD DCP, send control messages UPnP Bridge, and invoke each UPnP device. As a result, Electrical Appliance of Home Network base on UPnP, can control and be controlled via the Internet like ones in the one Home Network without modification of existing UPnP.