• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.38-41
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• 1997

As the LPM is used for position accuracy decision device it is required that both the reason of posion error and the definition of position itself should be cleared. In this study, the precision of the position decision of LPM is affected by the geometrical shape such as tooth shape or processing accuracy. By using the analysis of magnetic circuit, we calculated the permeance come up with the gap. Once the thrust force has been obtained, the permeance due to the mechanical error of the pole pitch and the tooth pitch becomes the error of thrust force. We confirmed as well that it is being affected by the difference due to the variation of the airgap permeance.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.828-829
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• 2008

This paper proposes a new pole shaped magnetizing fixture with a non uniform air gap for sinusoidal magnetizing a ring type permanent magnet (PM) to reduce the cogging torque. To obtain more sinusoidal distributed magnetic flux density, the magnetizing fixture's pole shape is optimized by using the sequential response surface method (RSM). And the effects of each design parameter were investigated using the magnetic analysis combined a time stepping finite element method (FEM) with Preisach model. It has been shown, through numerical analysis the optimized modelgives near sinusoidal distributed air gap flux density and drastically reduced cogging torque.

• Proceedings of the KAIS Fall Conference
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• 2008.11a
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• pp.433-435
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• 2008

본 연구에서는 MR 유체를 특징으로 하는 대시포트형 마운트를 제안하고, 자극 형상의 변화가 MR유체 마운트의 감쇠력에 미치는 영향에 대하여 고찰하였다. 제안된 MR유체 마운트의 코어부에 발생하는 자기 특성에 대하여 살펴보기 위하여 자극(Magnetic pole)의 유효길이와 코어 중심부의 구조를 달리하여 대시포트를 제작하였다. 등가자기회로를 이용한 대략적인 계산방법에 의한 결과 자극의 유효길이가 증가할수록 자기저항은 감소하는 경향을 나타내지만, 그 밖의 설계인자들의 영향은 작게 나타났다. 상용해석프로그램을 이용하여 등가자기회로 결과와 비교를 하였으며, 대시포트 마운트를 제작하여 자극의 유효길이 변화에 대한 감쇠력의 변화를 실험적으로 비교하였다.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.133-135
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• 1997

In this paper, we propose a new type of rotor construction in the permanent magnet synchronous motor. By using plural permanent magnets for one-role of the rotor, it is possible not only to reduce space harmonics of air-gap fields but also to provide spacs for damper windings in the inter-pole space. The dimensions of the plural permanent magnets are derived by Fourier analysis. Based on the investigation by numerical analyses. we propose an optimal rotor construction in view of both the reduction of space harmonics and the damping effect.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.1
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• pp.76-83
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• 2000

A 2-pole tunable bandpass filter was design and fabricated using ceramic coaxial resonators and varactor diodes for UHF band. By inspection of frequency characteristics of the T-and $\pi$-type inverter equivalent circuits, we can design a two-pole tunable BPF with only two varactors. The measured data of the filter show 800 MHz-900 MHz tunable center frequency range, 4.5 dB insertion loss, 0.5 dB passband ripple and at least 15 dB return loss, which agree well with the simulated results.

• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.68-71
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• 2003

An output multiplexer of manifold type is widely employed in a recent satellite transponder due to its small size and mass. For correct operation, channel fillers in manifold multiplexer must be singly terminated. In this paper, a simple synthesis method fur a single terminated filter is described. From the given method, a 4-pole singly terminated elliptic function filter for Ka band satellite transponder is designed. The filter is shown to be suitable for satellite application and its measured results agrees well with computed ones.

• Journal of Navigation and Port Research
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• v.30 no.7
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• pp.607-610
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• 2006

A new compact microstrip low-pass filter and its equivalent-circuit model are developed. The philosophy of the structure behind this novel microstrip low-pass filter is simple as it is composed of a pair of symmetrical parallel coupled-line and an open-stub. With this configuration, a finite attenuation pole near the stopband cutoff frequency is available and adjustable by simply tuning the circuit parameters. Furthermore, the rejection bandwidth of this type of low-pass filter can be extended. In order to validate the feasibility of the proposed design method, a low-pass filter based on a microstrip structure is designed, fabricated, and measured. Experimental results agree very well with the simulation and analytical results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.11
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• pp.2035-2042
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• 2011

In this paper, we proposed the outer-rotor type of FSPM motor for high speed operation and optimized motor shape. First of all, combinations of pole and slot numbers are examined for the optimal back-EMF and cogging torque, then optimizes the better shape design of the permanent magnet, rotor pole width. Further, The winding turns are obtained by circle of the voltage limit equation and motor parameters to minimize the current and to improve the efficiency. As a result, the performance of the designed model is satisfied, and it is verified through a two-dimensional finite element method (2D-FEA).

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.10a
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• pp.79-84
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• 2006

A novel design of compact low-pass filter based on microstrip structure and its equivalent-circuit model are developed. The philosophy of the structure behind this novel microstrip low-pass filter is simple as it is composed of a pair of symmetrical parallel coupled-line and an open-stub. With this configuration, a finite attenuation pole near the stopband cutoff frequency is available and adjustable by simply tuning the circuit parameters. Furthermore, the rejection bandwidth of this type of low-pass filter can be extended. In order to validate the feasibility of the proposed design method, a low-pass filter based on a microstrip structure is designed, fabricated, and measured. Experimental results agree very well with the simulation and analytical results.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.387-390
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• 2000

The life of transformer is significantly dependent on the thermal behavior in windings. To analyse winding temperature rise, many transformer designer have calculated temperature distribution and hot spot point by finite element method(FEM). Recently, numerical analyses of transformer are studied for optimum design, that is electric field analysis, magnetic field, potential vibration, thermal distribution and thermal stress. Therefore design time and design cost are decreased by numerical analysis. In this paper, the temperature distribution and thermal stress analysis of 50kVA pole cast resin transformer for power distribution are investigated by FEM program. The temperature change according to load rates of transformer also have been investigated. We have carried out temperature rise test and test results are compared with simulation data.