• 전력전자학회논문지
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• 제7권3호
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• pp.281-288
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• 2002

본 논문은 영구자석 여자 횡축형 선형 전동기(TFLM)를 이용한 가진기 제어 시스템을 구현하고자 한다. 제안된 가진기는 대상 물체에 정격 전류에서 최대 700[N]의 가진력과 넓은 변위 및 주파수 운전 범위를 갖는 진동운동을 제공한다. 또한 가진기에 적용된 TFLM은 구조적으로 높은 추력비(전동기 추력/전동기 중량=N/Kg)를 가지므로 전체 시스템의 부피가 감소된다. 따라서 기존의 유압식 가진기를 제안한 가진기로 대체할 경우 효율 및 유지, 관리면에서 많은 장점이 있다. 가진 제어를 위한 제어기의 입력은 가진 주파수와 변위이며 제어량은 이동자의 순시 위치와 속도이고 출력은 가진기에 인가되는 전류이다. 이 전류는 전압형 PWM 컨버터로 제어된다 우선 가진기 제어시스템의 제어 알고리즘과 운전 특성을 고찰하고 해석하기 위해 동적 시뮬레이션을 수행한 후 DSP 제어기와 IGBT PWM 컨버터를 구현하여 실제 실험 결과와 비친, 검토하였다.

• Journal of Electrical Engineering and Technology
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• 제10권6호
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• pp.2256-2261
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• 2015

In the power plant using high temperature fuel cells such as Molten Carbonate Fuel Cell(MCFC), and Solid Oxide Fuel Cell(SOFC), the generated electric power per area of power generation facilities is much higher than any other renewable energy sources. - High temperature fuel cell systems are capable of operating at MW rated power output. - It also has a feature that is short for length of the line for connecting the interior of the generation facilities. In normal condition, these points are advantages for voltage drops or power losses. However, in abnormal condition such as fault occurrence in electrical system, the fault currents are increased, because of the small impedance of the short length of power cable. Commonly, to minimize the thermal-mechanical stresses on the stack and increase the systems reliability, we divided the power plant configuration to several banks for parallel operation. However, when a fault occurs in the parallel operation system of power main transformer, the fault currents might exceed the interruption capacity of protective devices. In fact, although the internal voltage level of the fuel cell power plant is the voltage level of distribution systems, we should install the circuit breakers for transmission systems due to fault current. To resolve these problems, the SFCL has been studied as one of the noticeable devices. Therefore, we analyzed the effect of application of the SFCL on bus tie in a fuel cell power plants system using PSCAD/EMTDC.

• Journal of Advanced Marine Engineering and Technology
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• 제35권1호
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• pp.96-101
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• 2011

본 연구에서는 수평축 조류발전용 터빈 블레이드 설계 및 성능평가가 가능하도록 블레이드 끝단 손실모델을 고려한 블레이드요소 운동량 이론을 적용하여 설계를 수행함으로써 관련 설계기법을 확립하였고 최종적으로 설계 및 성능평가를 위한 국산 소프트웨어의 개발을 완료하였다. 개발된 성능평가 소프트웨어인 MCT-Blade V2.0을 통해 2MW급 블레이드 설계 및 성능평가를 수행하였으며, ANSYS FLUENT 상용코드를 이용하여 BEMT에 의한 성능평가 결과의 타당성을 검증하였다. 2.5m/s 정격유속에서 BEMT에 의한 기계적 출력은 2,121kW로써 전기적 출력을 만족하였지만, CFD에 의한 기계적 출력은 1,901kW로써 목표출력에 다소 부족한 결과를 보였다.

• 보건교육건강증진학회지
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• 제26권1호
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• pp.63-80
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• 2009

Objectives: This study identified how personal characteristics, healthy behavior and social capital might influence on physical activity of adults. Methods: This study used data from the health survey of a city of Korea. We surveyed 1,000 adults sampled by stratified sampling methods from 67,889 households. Outcome variable was the stage of physical activity which was broken into 5 categories. Sociodemographic factors, healthy behavior, self-rated health status and social capital were used as control variables. Sociodemographic factors included age, sex, educational status, economic status measured by deprivation score, residential period within survey city. Social capital was measured by Integrated Questionnaire for the Measurement of Social Capital (SC-IQ). This study used chi-square test and ordered logistic regression models to examine the associations between independent variables and physical activity. Variables were added to the regression model in three groups using a hierarchical approach. Results: Physical activity was significantly more likely to become active if they have higher educational status, healthier behavior. Among the six dimensions of SC-IQ, only "groups and networks" that is structural dimensions of social capital and "trust and solidarity" that is cognitive dimensions of social capital were significantly related to physical activity of adults. We found that a person having higher density of membership and having larger size of networks showed the high possibility of active physical activity. A person having high solidarity was significantly associated with physical activity, but general trust was inversely related to physical activity. Output dimensions of social capital did not show significant relationship to physical activity. Conclusion: We found that social capital is useful concept to explain health behaviors like physical activity. However we must consider social, cultural and political context of the study to evaluate the effect of social capital to health status and health determinants and to capture the exact meaning of relationship between them. We suggest further researches to refine the concept of social capital and to explain the relationship of social capital to diverse health determinants.

• 센서학회지
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• 제20권3호
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• pp.172-177
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• 2011

Finger patients can't use their hands because of the paralysis their fingers. Their fingers are recovered by rehabilitating training, and the rehabilitating extent can be judged by measuring the pressing force to be contacted with two fingers(thumb and first finger, thumb and middle finger, thumb and ring finger, thumb and little finger). At present, most hospitals have used a thin plastic-plate for measuring the two-finger grasping force, and we can only judge that they can grasp the plate with their two-finger through it, because the plate can't measure the two-finger grasping force. But, recently, the force measuring system for measuring two-finger grasping force was developed using three-axis force sensor, but it is very expensive, because it has a three-axis force sensor. In this paper, two-finger force measuring system with a one-axis force sensor which can measure two-finger grasping force was developed. The one-axis force sensor was designed and fabricated, and the force measuring device was designed and manufactured using DSP(Digital Signal Processing). Also, the grasping force test of men was performed using the developed two-finger force measuring system, it was confirmed that the grasping forces of men were different according to grasping methods, and the system can be used for measuring two-finger grasping force.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 추계학술발표대회 논문집
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• pp.356-360
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• 2009

Recent global environmental pollution and contamination and depletion of limited fossil energy prices surge as an energy source to replace it depending on wind, fuel cells and solar power and other renewable and pollution free renewable energy is of interest in increase. The photovoltaic systems are pollution-free, unlimited energy source, and easy to install because it is rated as the most valuable renewable energy sector and the prevalence is spreading throughout the world. Photovoltaic systems at one end of the stable development of the role that solar power inverter applications can be the most important. No matter how much power the solar arrays, even if the inverter output in the normally if he's no use. These photovoltaic inverters to evaluate the performance of the inverter efficiency measures that can be called directly. This way of measuring the efficiency of solar inverters in Europe efficiency and CEC efficiency is currently being used. In this paper, until now about how to measure the efficiency of solar power inverter technology and the new Korean Meteorological Solar Insolation data analysis to derive weights based on this inverter efficiency for Korea is to offer.

• 조명전기설비학회논문지
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• 제23권12호
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• pp.224-232
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• 2009

화력발전소를 기동하기 위해서는 수많은 기기조작들이 수동 및 자동으로 또한 순차적 및 병렬로 정확하게 진행되어야 한다. 따라서 발전소의 기동 중 긴박하게 이루어지는 수많은 기기 조작들이 모두 제대로 진행되고 있는지의 여부를 실시간으로 감시하는 일은 매우 복잡하고 긴장을 요하는 임무(task)이다. 본 논문에서는 화력 발전소의 기동시퀀스의 정상 진행 여부를 효과적으로 감시하기 위하여 Event Sequence Monitoring Graph(ESMG)라는 자료구조(Data Structure)를 제안하고 그 구현 기법에 대하여 논하고자 한다. 제안하된 ESMG는 용량 500MW 급의 국내 전형적인 표준형 화력발전소의 주 급수펌프 시스템의 기동 시퀀스의 진행 감시에 적용하기 위한 예를 들었으며 향후 유용하게 활용될 수 있는 가능성을 보였다.

• 전기학회논문지
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• 제65권7호
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• pp.1151-1160
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• 2016

In recent years, the energy storage systems such as LiB, NaS, RFB(Redox-Flow Battery), Super- capacitor, pumped hydro storage, flywheel, CAES(Compressed Air Energy Storage) and so on have received great attention as practical solutions for the power supply problems. They can be used for various purpose of peak shaving, load leveling and frequency regulation, according to the characteristics of each ESS(energy storage system). This paper will focus at 1 MWh RFB system, which is being developed through the original technology project of energy material. The output of ESS is mainly characterized by C-rate, which means that the total rated capacity of battery will be delivered in 1 hour. And it is a very important factor in the ESS operation scheduling. There can be several options according to the operation intervals 15, 30 and 60minutes. The operation scheduling is based on the optimization to minimize the daily electricity cost. This paper analyzes the cost-saving effects by the each operating time-interval in case that the RFB ESS is optimally scheduled for peak shaving and load leveling.

• 해양환경안전학회지
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• 제25권1호
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• pp.117-121
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• 2019

본 연구에서는 국내외적으로 환경문제 및 에너지절감의 일환으로 직류배전시스템을 선박에 적용하려는 연구 및 실증이 활발히 수행되고 있으며, 발전기를 직류배전시스템에 적용하기 위해서는 가변속 엔진을 적용하여 저부하 영역에서 발전기의 엔진 회전수를 줄여 연료소모량을 절감할 수 있는 방안이 제시되고 있다. 본 논문에서는 기존의 디젤발전기를 이용하여 발전기 컨트롤러, 가버너, AVR을 이용하여 직류배전용 가변속발전기를 구성하였으며, 발전기의 시스템 구성 방법, 가변속 발전에 따른 전력품질 시험(전압 및 주파수 변동특성, 부하변동 특성)을 통해 가변속 발전기의 전력특성을 분석 하였다. 가변속 발전기의 전압(250 ~ 440 VAC) 및 주파수(34 ~ 60 Hz)는 정격의 60 ~ 100 %로 구성하였으며, 엔진은 1100 ~ 1800 rpm 범위에서 운전되도록 설정 하였다. 부하변동에 따라 발전기의 엔진속도를 변경시켜서 발전기 출력의 전압, 전류, 주파수가 전력량에 따라 안정적으로 변동되는 것을 확인하였다.

• 한국인터넷방송통신학회논문지
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• 제21권4호
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• pp.117-122
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• 2021

영구자석 동기전동기는 높은 출력밀도와 효율 확보가 가능하나, 제작에 필요한 재료의 가격이 비싸고 설계가 유도전동기 대비 다소 어려운 문제점을 가지고 있다. 따라서 효율 및 유지보수 편의성 등이 모두 고려된 최적의 전동기 개발 및 관련 제어연구가 필요한 실정이다. 뿐만 아니라, 실질적인 전동기에 의한 구동은 좁은 정격영역에서의 최고효율의 증대 요구와 전체 전기구동 영역에서의 평균 효율 증대, 평균 출력의 증대 요구로 이어지고 있다. 이러한 움직임에 의해 영구자석이 필요 없는 릴럭턴스 전동기 (Reluctance Motor)가 하나의 대안으로 검토되고 있다. 본 논문에서는 희토류 영구자석 전동기를 대체할 수 있는 미래기술 개발과, 희토류 저감형 전동기와 탈 희토류 전동기의 기술 선점을 요구하는 시대적 이슈 (Issue)에 맞춰 영구자석이 필요 없는 스위치드 릴럭턴스 전동기 (Switched Reluvtance Motor, SRM)에 대해 기계언어(C 언어)를 통한 modeling과 그에 따른 SRM의 특성을 연구하고자 한다.