• Proceedings of the KIEE Conference
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• 2008.04c
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• pp.233-235
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• 2008

본 논문에서는 신 재생에너지원 중 큰 축을 이루고 있는 태양광과 연료전지 발전시스템을 연계하여 하이브리드 발전시스템에 대하여 제안하였다. 태양광으로부터 발생되는 전력을 이용하여 부하에 공급함과 동시에 수전해장치를 구동시키고, 수전해장치는 전기분해시 필요한 전력을 태양광으로부터 공급받아 수소를 생산하게 된다. 본 시스템은 앞으로 가정에 적용될 수 있는 분산전원용 발전시스템의 기초 연구로써 신 재생에너지의 보급확대에 큰 기여를 할 것으로 사료된다.

• Journal of Welding and Joining
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• v.21 no.4
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• pp.25-30
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• 2003

There have been many researches for small scale packages such as CSP, BGA, and Flipchip. Underfill encapsulant technology is one of the latest assembly technologies. The underfill encapsulant could enhance the reliability of the packages by flowing into the gap between die and substrate. In this paper, the effects of underfill packages by both aspects of thermal and mechanical reliabilities are studied. Especially, it is focused to value board-level reliability whether by the underfill is applied or not. First of all, The predicted thermal fatigue lifes of underfilled and no underfilled $\mu$ BGA solder joints are performed by Coffin-Manson's equation and FEA program, ANSYS(version 5.62). Also, the thermal fatigue lifes of $\mu$ BGA solder joints are experimented by thermal cycle test during the temperature, 218K to 423k. Consequently, both experimental and numerical study show that $\mu$ BGA with underfill has over ten times better fatigue lift than $\mu$ BGA without underfill.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.7
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• pp.1281-1286
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• 2009

As a general radial configuration of power distribution system, the various researches have being studied to change a radial configuration to network one such as smart, intelligent and micro grid for loop operation. If a radial configuration changes to network, protective coordination comes to the biggest problem. When a typical protective algorithm is applied to loop distribution system protection, the interrupted section is expanded, therefore, reliability grows worse. This paper presents the new protective method being able to apply to loop distribution system with Distribution Automation System (DAS) which separate the minimal faulted section. Through contingency analysis of the sustained and momentary fault, we analyzed the influence for radial configuration and loop configuration using interrupted area and proved the effectiveness of proposed method.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.437-442
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• 2005

In this paper, we proposed the 2-dimensional inspection algorithm for micro-BGA(Ball Grid Array) device using a vision system. The proposed method uses the subpixel algorithm for high precision. The proposed algorithm preferentially extracts the package area of device in the input image. After the extraction of package area, each ball areas are extracted by ball search window method. The parameters for inspection are calculated for the extracted ball area. In the simulation results, we have the average error within $17{\mu}m$.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1045_1046
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• 2009

This paper presents an active and reactive power compensator for the wind power system with squirrel-cage induction generator. The developed system is able to continuously compensate the active and reactive power. The 3-phase inverter operates for the compensation of reactive power, while the DC/DC converter with super-capacitors operates for the compensation of active power. The proposed compensator can be expected that developed system may be used to compensated the abrupt power variation due to sudden change of wind speed or sudden power-drop by tower effect. It can be also applied for the distributed generation and the Micro-Grid.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.246_247
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• 2009

본 논문에서는 여러 가지 과도현상 해석 프로그램 중 하나인 EMTP-RV시뮬레이터를 이용하여 태양전지와 연료전지에 의해 각각 발생되어진 에너지원을 공통의 DC-BUS에 연계하여 운전하는 마이크로 소스와 마이크로그리드를 모델링하였다. 또한 사례 연구를 통해 마이크 로그리드의 운전형태와 부하변동에 따른 마이크로소스의 동특성을 분석하였다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.70_71
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• 2009

최근 높은 전력 품질을 요구하는 수용가의 증가와 지구온난화 방지 규제에 저탄소 친환경의 신재생에너지 발전의 요구가 증가하고 있다. 또한 에너지 비용 절감을 위해 열병합 발전이 증가 추세에 있으며 이러한 발전원들은 열과 전기가 필요한 수용가 깊숙이 자리를 하고 있다. 그러나 이러한 요구에 반하여 마이크로 발전원들의 부정적인 영향이 상용 전원 및 배전계통에 무시할 수 없는 영향을 미치고 있다. 따라서 이러한 발전원에 의한 불안정적인 요소를 제거하고 안정적이며 경제적인 배전계통의 운영을 위해 마이크로 그리드 내에서의 발전원 제어 기술이 필요하며 제어에 필요한 발전요소들의 경제적인 투자와 운영이 필요하다. 따라서 본 논문에서는 이러한 마이크로 그리드 내에서의 발전원 제어를 위해 필요한 요소 발전원 중 배터리용량을 경제적으로 산출하고 운영하는 방안을 제시하고자 한다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.7
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• pp.55-62
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• 2011

PCS(Power Conditioning System) is the necessary component in Microgrid, composed of multiple distributed generators and energy storage system. In this paper, the functions of PCS are defined and 10[kW] PCS for PV and BESS are developed. To apply PCSs to Microgrid, this paper presents a 3-phase inverter with the decoupling current controller, voltage controller and DPLL control system. PCSs were applied to 120[kW] pilot plant and its performance tests were carried out. Test results of PCS at each operation mode show stable in Microgrid.

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.93-94
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• 2014

본 논문의 주제는 가파도 마이크로 그리드에 적용한 1MVA급 배터리 에너지 저장시스템(BESS-Battery Energy Storage System)을 소개하는 것이다. 에너지 저장장치가 디젤발전기와의 연계 및 독립운전 하여 탄소 배출 없이(Carbon-Free) 가파도 전체 부하에 전원을 공급하는 실증 사례를 살핀다.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.852-855
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• 2010

Numerical simulations for large scale triaxial tests with large diameter rockfill materials are conducted using distinct element method. For generation of compacted assembly with specific grain size distribution and initial material porosity, the clump logic method and expansion of generated particles are adapted. With micro parameters which are chosen by calibration process, discrete particle modelling of triaxial test in case of other confining stress and cyclic loading condition were conducted. Also numerical simulations of fluid injection into particulate materials were conducted to observe cavity initiation and propagation using distinct element method. The fluid scheme solves the continuity and Navior-Stokes equations numerically, then derives pressure and velocity vectors for fixed grid by considering the existence of particles within the fluid cell.