• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.16-18
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• 2006

유한요소법을 사용한 전기기기의 해석에서는 움직임을 고려한 해석이 필수적이다. 본 논문에서는 전기기기의 유한요소 해석시 움직임을 고려하기 위한 방안으로써 Moving Suface기법을 소개하고 이 기법의 적용방법 및 장단점에 관하여 논하였다. 또한 이 기법을 검증하기 위하여 Moving Surface기법을 적용한 유한요소해석 프로그램을 개발하고, 개발한 프로그램을 사용하여 실제 모델을 해석해 그 결과치를 실험치와 비교함으로써 타당성을 입증하였다.

• 한국해양공학회지
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• 제4권1호
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• pp.43-48
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• 1990

The results of previous works on the wave energy conversion do not seem to be satisfactory due to irregularity, and the non-linear hydrodynamic effect which is inevitably featured due to the structural complexity of the ocean wave energy conversion device. These may cause the difficulty estimating the extracted wave power. In this paper a study on estimating the extracted wave power and its ratio. The present authors have developed another method estimating the extracted wave power using the three dimensional source distribution method, which was turned out to be an improved one. It has been observed that the present results may be used for the control of the wave energy conversion device and the optimal design has been derived from the several case studies.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.169-171
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• 2007

A breaking layer was introduced to conventional decal transfer method in membrane electrolyte assembly fabrication for high catalyst transfer ratio. In this study, the modified decal transfer method with high catalyst transfer ratio was introduced and its performance is studied. The structural features of electrodes made by decal method were investigated using scanning electron microscopy and current-voltage polarization measurement.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제11B권4호
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• pp.156-163
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• 2001

In this paper an optimal switching angle control of a switched reluctance motor (SRM) drive system is investigated for achieving maximum energy conversion ratio. A new magnetizing method is proposed with a low switching frequency. The proposed algorithm maximizes the positive energy conversion region, which is directly related to the mechanical output, and reduces the reactive power region with the same field energy region. As a consequence, a torque ripple is also sufficiently reduced compared with that of the conventional switching angle magnetizing method. Experimental results show that the proposed scheme provides a high efficiency and a low ripple drive.

• Journal of Magnetics
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• 제16권4호
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• pp.379-385
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• 2011

This paper presents an optimal design of a direct-drive permanent magnet synchronous generator for a small-scale wind energy conversion system. An analytical model of a small-scale grid-connected wind energy conversion system is presented, and the effects of generator design parameters on the payback period of the system are investigated. An optimization procedure based on genetic algorithm method is then employed to optimize four design parameters of the generator for use in a region with relatively low wind-speed. The aim of optimization is minimizing the payback period of the initial investment on wind energy conversion systems for residential applications. This makes the use of these systems more economical and appealing. Finite element method is employed to evaluate the performance of the optimized generator. The results obtained from finite element analysis are close to those achieved by analytical model.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권8호
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• pp.374-383
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• 2001

This paper presents the torque estimation scheme by Energy Conversion Method (ECM) that can be applied to the torque control of switched reluctance motor. There are two types of torque estimation method by ECM. One is the method using mechanical output energy and another is that using co-energy. When the torque is estimated by ECM, the estimated flux linkage can be obtained by voltage equation and Luenberger observer. By comparing the torque estimated by ECM with that be FEM, we verify the feasibility of the proposed torque estimation by ECM.

• Bulletin of the Korean Chemical Society
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• 제31권9호
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• pp.2447-2448
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• 2010

• 설비공학논문집
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• 제28권2호
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• pp.75-80
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• 2016

There are three types of dehumidification systems : refrigeration dehumidification method, desiccant dehumidification method and hybrid dehumidification method. The first method involves removing moisture by condensation below the dew point, the second method involves absorption by a desiccant material and the last is an integration method. However, the refrigeration dehumidification system consumes too much power and controlling the humidity ratio is difficult. The desiccant dehumidification system uses less power but it has problems of environmental pollution. The hybrid dehumidification system has the disadvantage of a high initial cost. On the other hand, the energy consumption of the membrane based dehumidification system is lower than for the refrigeration dehumidification system. Also, it is an environmentally friendly technology. In this study, the performance parameters are evaluated for the dehumidification system using a hollow fiber membrane. Available area, duct side dry-bulb temperature, sweep gas flux (flow rate) and LMPD (Log Mean Pressure Difference) were used as the performance parameters.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.165.1-165.1
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• 2011

In the present study, two numerical methods were developed and compared for the performance prediction of the horizontal axis energy conversion turbine. The Blade Element Momentum Theory was adopted, and the rotating reference frame method for Computational Fluid Dynamics solver was also used. Hybrid meshing was used for the complex geometry of turbines. The analysis results using each method were compared to figure out a better method for the performance prediction.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.354-355
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• 2006

We manufactured photoelectrode of dye-sensitized solar cells (DSC) by using three methods such as squeeze method, spray method, and combination method (squeeze method first, spray method second). We examined how the morphology of an electrode's surface, the pore between particles, and condensation have an effect on an open-circuit voltage, photocurrent, fill factor, and energy conversion efficiency. Open-circuit voltage of dye-sensitized solar cells manufactured by using three methods is about 0.66V when the photoelectrode of the three DSCs is about $5{\mu}m$ thick. Photocurrent and fill factor and conversion efficiency of DSC manufactured by using squeeze method is 18.5 and 34 and 7.8, respectively. Photocurrent and fill factor and conversion efficiency of DSC manufactured by using spray method is 3.62 and 62 and 2.8, respectively. Photocurrent and fill factor and conversion efficiency of DSC manufactured by using combination method is 10.7 and 46 and 5.9, respectively. In conclusion, we find that the combination method is better than the other two methods in such respects as energy conversion efficiency and fill factor.