• 전자공학회논문지
• /
• 제50권2호
• /
• pp.174-184
• /
• 2013

LED 기반 그린에너지 조명 시스템의 성공적인 연구 개발과 원만한 설치 운영을 위해서는 펄스 파, 스파이크 파를 비롯한 비선형신호와 고조파, sag, swell 등을 포함한 불요신호에 대한 실시간 전력품질측정이 요구된다. 본 논문에서는 그린에너지 조명시스템 응용을 타깃으로 기존 저주파수 대 (60Hz~수KHz)는 물론 수십 KHz 이상의 고주파수 대에 발생하는 각종 전원 신호 분석이 가능한 저가형 전력품질측정 (power quality measurement: PQM) 방안을 제안하고, 이를 TI 320F28335 MCU(micro-controller unit) 기반 PQM 테스트 베드로 구현한다. 제안된 알고리즘은 CCS (Code Composer Studio) 3.3 환경에서 C언어로 작성하였으며, 임의 신호 발생기(NF-WF1974)로부터 발생된 모의 신호를 활용하여 구현된 알고리즘을 검증한다. 테스트 베드를 이용하여 LED SMPS로부터 발생되는 각종 비선형 전류 신호 측정, FFT를 이용한 고조파 신호의 분석이 가능할 뿐 아니라 이산 웨이블렛 변환을 이용한 sag, swell, interruption 등의 고품질 전력신호 측정도 가능하다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.71-73
• /
• 2006

AC loss on variation of external magnetic field is a very important factor in development of power applications. In this paper, we measured and compared AC loss of hybrid-multi stacked wire made of the combination of 1G wires and 2G wires and uniform-multi-stacked wire made of one type of wires, 1G wires or 2G wires. Measurement was performed using by the linked-picked coil method. As results, as the number of wires increase, AC loss per unit volume of both stacked wires in low external magnetic field is reduced. Also AC loss of 2G slacked wire is higher than that of 1G wire. AC loss per unit length of 2G stacked wire is less than that of 1G stacked wire. And AC loss of hybrid-multi stacked wire made of the combination of 1G wires and 2G wires was between uniform-multi-stacked wire made of 1G wires and 2G wires.

• 한국안전학회지
• /
• 제25권5호
• /
• pp.15-21
• /
• 2010

Regenerative Energy Storage System(ESS) is a system that saves regenerative energy which generated instantly in the regenerative braking of Electric Multiple Unit(EMU) and disappear, and reuse the stored energy when EMU is in powering. Such system related to a research field of renewable energy which emerged concerning climate change and high oil prices. In the case of existing domestic rolling stock, about 25% to 30% of generated regenerative energy is restored to power source and is regarded as direct factor of raising catenary voltage. Such rapid change of catenary voltage is a cause of the failure of EMU's electronic equipment and lowering its reliability and is also a cause of train's fault occurred by tripping circuit breaker. In this paper, we intend to investigate the effect on blending characteristics of electric-braking and pneumatic-braking whether the regenerative energy storage system is used or not in urban transit DC 1,500V feeding system, while trains run. And we also intend to investigate its effect on stabilization of the blending, fluctuation of catenary voltage and various electric equipments.

• Bulletin of the Korean Chemical Society
• /
• 제28권8호
• /
• pp.1311-1316
• /
• 2007

To develop photo-sensitizers for dye-sensitized solar cells (DSCs) used in harvesting sunlight and transferring solar energy into electricity, we synthesize novel Ru(II) polypyridyl dyes and describe their characterization. We also investigate the photo-electrochemical properties of DSCs using these sensitizers. New dyes contain chromophore unit of dafo (4,5-diazafluoren-9-one) or phen-dione (1,10-phenanthroline-5,6-dione) instead of the nonchromophoric donor unit of thiocyanato ligand in cis-[RuII(dcbpy)2(NCS)2] (dcbpy = 4,4'-dicarboxy- 2,2'-bipyridine) coded as N3 dye. For example, the photovoltaic data of DSCs using [RuII(dcbpy)2(dafo)](CN)2 as a sensitizer show 6.85 mA/cm2, 0.70 V, 0.58 and 2.82% in short-circuit current (Jsc ), open-circuit voltage (Voc), fill factor (FF) and power conversion efficiency (Eff), which can be compared with those of 7.90 mA/ cm2, 0.70 V, 0.53 and 3.03% for N3 dye. With the same chelating ligand directly bonded to the Ru metal in the complex, the CN ligand increases the Jsc value by double, compared to the SCN ligand. The extra binding ability in these new dyes makes them more resistant against ligand loss and photo-induced isomerization within octahedral geometry.

• Nuclear Engineering and Technology
• /
• 제26권3호
• /
• pp.411-419
• /
• 1994

원자력발전소 중대사고시 예상되는 수소생성과 이에 따른 수소연소로 인한 압력증가로 야기되는 격납용기의 파손화률을 몬테카를로 방법을 통하여 계산하였다. 몬테카를로 계산을 수행하기 위해서는 각각의 입력변수들에 대한 적절한 확률분포함수가 요구되는데, 통계적인 처리를 통하여 구하였다. 고리 2호기에 대한 계산을 수행하였으며, 입력변수들에 대한 민감도 분석도 실시하였다. 고리 2호기에서 수소연소로 인한 격납용기의 파손확률은 60% 이하로 계산되었으며, 민감도 분석결과 SFD가 중요한 인자이긴 하지만 다른 인자들도 무시할 수 없는 영향을 미치고 있음이 밝혀졌다.

• 한국지진공학회논문집
• /
• 제27권6호
• /
• pp.311-320
• /
• 2023

When an earthquake occurs, the severity of damage is determined by natural factors such as the magnitude of the earthquake, the epicenter distance, soil properties, and type of the structures in the affected area, as well as the socio-economic factors such as the population, disaster prevention measures, and economic power of the community. This study evaluated the direct economic loss due to building damage and the community's recovery ability. Building damage was estimated using fragility functions due to the design earthquake by the seismic design code. The usage of the building was determined from the information in the building registrar. Direct economic loss was evaluated using the standard unit price and estimated building damage. The standard unit price was obtained from the Korean Real Estate Board. The community's recovery capacity was calculated using nine indicators selected from regional statistical data. After appropriate normalization and factor analysis, the recovery ability score was calculated through relative evaluation with neighboring cities.

• 대한기계학회논문집B
• /
• 제26권6호
• /
• pp.805-810
• /
• 2002

Development of a small gas-turbine combustor for 100㎾ class APU(Auxiliary Power Unit) has been performed. This combustor is a reverse-annular type and has a tangential swiller in the liner head to improve the fuel/air mixing and flame stability. Three main and three pilot fuel injectors of the simplex pressure-swirl type are used. The performance target at the design condition includes a turbine inlet temperature of l170k, a combustion efficiency of 99%, a pattern factor of 30%, and an engine durability of 3000 hours. Under developing the combustor, we conducted the performance test of our first prototype(TS1) with some variants. As a result of the test, the performance targets of the combustor are satisfied except that the pattern factor is about 4% higher than the target value. Therefore, the second prototype(TS2) was redesigned and the performance test was conducted with the critical focus on the pattern factor and the exit mean temperature. We adopted TS2 four variants to check the improvement of the pattern factor. As a result, the pattern factors of several variants were satisfied with the performance target. Finally, the TS2A variant was chosen as a final combustor fur our APU model.

• 전기학회논문지
• /
• 제65권5호
• /
• pp.843-850
• /
• 2016

In this paper, we propose a digital controller design process for the interleaved type of a boost PFC (Power Factor Correction) converter which can disperse the heat of the switching devices due to the interleaved topology. We establish a mathematical model of a boost PFC converter and propose a controller design method based on the root locus. The performance of the designed controller is verified by simulations. The measurement of the input voltage, inductor currents, and the converter output link voltage are needed for the control of the converter system which consists of a power unit and a control unit where a high-performance 32-bit microcontroller is used. The adjustment of A/D conversion timing is also needed to avoid high frequency noise generated when the switches on/off. It is illustrated by the real experiments that the designed control system with the properly adjusted ADC timing satisfies the given performance specifications of the interleaved boost PFC converter in the on-board slow battery charger.

• 플랜트 저널
• /
• 제14권3호
• /
• pp.29-34
• /
• 2018

본 연구에서는 태안석탄가스화복합발전을 대상으로 대기온도에 따른 출력 및 열효율 변화를 제작사의 기본설계자료와 대기온도별 성능보정계수를 이용하여 계산하였으며, 하계 및 동계 대표지점에서 실제 성능을 측정하고 그 결과를 계산값과 비교하여 타당성을 확인하였다. 열효율은 $15^{\circ}C$ 부근에서 가장 높고 이보다 저온이나 고온에서는 낮아지는데 이는 천연가스복합발전과 유사하였으나, 상대적으로 고온구간에서는 공기분리장치의 소비동력증가로 열효율이 급격히 하강하였다. 또한 출력은 $5{\sim}15^{\circ}C$ 구간에서 가장 높고 $5^{\circ}C$ 이하에서는 거의 일정하게 유지되며 $15^{\circ}C$ 이상에서는 하락한다. 저온에서 출력이 증가하지 않는 이유는 가스터빈 연소기 질소주입에 따른 유량 증가로 축의 토크 제한이 작동하기 때문이다. 향후 성능향상을 위해서는 하계에 발전출력향상 및 공기분리장치 소비동력 저감 등의 노력이 필요하다.

• 정보저장시스템학회:학술대회논문집
• /
• 정보저장시스템학회 2005년도 추계학술대회 논문집
• /
• pp.154-159
• /
• 2005

The next generation of optical storage systems requires higher numerical aperture (NA) objective lenses and shorter wavelength laser in order to improve the unit areal density. A blu-ray technology satisfies a miniaturization and a high capacity which are the requirements of the portable device. In this paper, we analyze the optical performance of hybrid micro lens and do active alignment. The hybrid micro lens is manufactured by using a wafer based fabrication technology. Optical components of hybrid micro lens are evaluated. The measurement of the optical power, the spot size and the wavefront error awe performed to evaluate the hybrid micro lens with NA 0.85. Using the measured data, we estimate if the performance of hybrid micro lens corresponds to the designed performance. After the performance of hybrid micro lens is evaluated, the integrated optical pickup and the hybrid micro lens are assembled by active alignment using UV curing and the optical performance of SFFOP is satisfied with BD specifications.