Back to bock 컨버터를 갖는 가변속 풍력터빈 시스템의 모델링과 해석

김일환,강경보,김재홍,문상호,오성보,김세호,Kim, Eel-Hwan,Kang, Keong-Bo,Kim, Jae-Hong,Moon, Sang-Ho,Oh, Sung-Bo,Kim, Se-Ho 한국조명전기설비학회 2005 조명·전기설비학회논문지 Vol.19 No.8

본 논문에서는 이중여자 유도발전기의 회전자에 back to back 컨버터가 채용된 가변속 풍력터빈 시스템의 모델링과 해석을 나타내었다. 제어시스템의 특성을 파악하기 위해서 시뮬레이션에서는 Psim 프로그램을 사용하여 660[kW] 의 출력정격을 갖는 시스템을 모델로 하였다. 모델링에서는 블레이드 제어 시스템 모델과 회전자와 계통선에 연결된 컨버터 시스템을 모델링 하였다. 풍속의 변화에 따라 원하는 출력을 얻을 수 있도록 피치각을 제어하여 정격풍속 이하에서도 최대출력이 발생하도록 하였고, 정격풍속 이상에서는 회전자 속도를 일정하게 하여 정격출력을 유지할 수 있도록 하였다. 또한 무효전력을 제어하여 출력의 역률을 제어하였다. 제안한 해석방법의 타당성을 검증하기 위하여 풍속변화에 따른 모델 시스템의 시뮬레이션 결과 값들과 제주행원 풍력발전 단지에서 운용되고 있는 V47 660[kW] 시스템의 실측 결과들과 서로 비교 검증하여 제안한 해석 방법의 타당성을 입증하였다. This paper presents the simulation modeling and analysis of variable wind speed turbine system(VWTS) using the doubly fed induction generator(DFIG) connected the back to back converter system in the rotor side. In the simulation, using the model system which has the 660[kW] rated power, blade control and the dual converter system are modeled for verifying the control characteristics. The VWTS is controlled by the optimal pitch angle for maximum output power under the rated wind speed, and for the rated output power over the rated wind speed. And also power factor is controlled by the reactive power. To verify the effectiveness of the proposed method, simulation results are compared with the actual data from the V47 VWTS located in Hangwon wind farm in Jeju-Do. According to the comparison of these results, this method shows excellent performance.

Chlamydophila psittaci에 감염된 앵무새의 임상병리학적 특징과 원인균의 ompA 유전자 비교분석

김일환,장진욱,이수형,김대용,성원진,권혁준,김재홍,Kim, Il-Hwan,Jang, Jin-Wook,Lee, Su-Hyung,Kim, Dae-Yong,Seong, Won-Jin,Kwon, Hyuk-Joon,Kim, Jae-Hong 대한수의학회 2012 대한수의학회지 Vol.52 No.3

Avian chlamydiosis is caused by Chlamydophila psittaci and considered as one of an important zoonotic disease throughout the world. Among more than 400 avian species including poultry and pet birds susceptible to the disease, psittacine birds were known to be mostly susceptible hosts. In Korea, no outbreak of the disease and genetic analysis of the agent in poultry and pet birds have been reported. With histopathological findings and genetic identification of a causative agent, avian chlamydiosis was identified in parrots submitted from the same pet bird farm in 2006 and 2009 for the diagnosis. Based on genetic sequences and phylogenetic analysis of ompA gene, the two isolates of Chlamydophila psittaci showed 100% of genetic similarity and belonged to genotype A, suggesting that the same agent might be continuously circulated in the farm. This result indicates that serological survey of the disease in pet bird farms and impact of the disease on significance in public health may be further studied.

김남천 소설의 어휘 사용 양상에 대한 계량적 연구

문한별(Han Byoul Moon),김일환(Il Hwan Kim) 한국현대소설학회 2011 현대소설연구 Vol.- No.48

This paper aims to investigate characteristics of use of lexical items in Kim, Namcheon`s novels based on quantitative and statistical approach. It is well known that trends of Kim`s novel have seriously changed after KAPF was dismissed. However there are few researches how this kind of changes can be affected in his novels concretely. It is expected that quantitative approaches on Kim`s novels are able to overcome this kinds of limit. Especially in this paper, in order to analyze his novels, first, we developed his 17 representative novels to raw corpus, and then annotated linguistic information, part-of-speech to the corpus. From the annotated corpus, we can get the frequencies of words(nouns) by works and part-of-speeches. However even most frequent words in the text are not always meaningful to analyze the text. So statistical verification as a t-score must be applied in the process of extracting keywords. As a result we are able to find some keywords in 17 texts explicitly and trends of Kim`s novels are explained by year and work in a successful way.

인산염이 쌀전분 현탁액의 리올로지에 미치는 영향

김일환,김성곤,이신영,Kim, Il-Hwang,Kim, Sung-Kon,Lee, Shin-Young 한국식품과학회 1987 한국식품과학회지 Vol.19 No.3

쌀 전분현탁액(5%)의 리올로지 특성을 모세관 점도계를 이용하여 조사하였다. 멥쌀 전분은 $30{\sim}60^{\circ}C$에서, 찹쌀 전분은 $30{\sim}55^{\circ}C$에서 인산염의 첨가 유무에 관계없이 항복응력이 없는 팽창유체 (dilatant fiuid)의 거동을보였다. 그러나 멥쌀 전분은 $65^{\circ}C$에서, 찹쌀 전분은$60^{\circ}C$에서 의가소성 유체의 거동을 보였다. 인산염의 첨가시 멥쌀 전분은 의가소성이 증가하는 현상을 보인 반면, 찹쌀 전분의 경우에는 뚜렷한 증가를 보이지 않았다. 온도 $30{\sim}50^{\circ}C$의 경우 전분현탁액의 유동의 활성화 에너지는 $0.88{\sim}1.45kcal/mole$이었으나, $60{\sim}65^{\circ}C$의 경우에는 멥쌀 전분이 약73kcal/mole, 찹쌀 전분이 45.57kcal/mole이었다. 인삼염의 첨가시에는 $89.39{\sim}182.89kcal/mole$이었으며, 아끼바레가 가장 높은 값을 찹쌀이 가장 낮은 값을 보였다. Rheological properties of 5% starch suspension were investigated using a capillarity tube viscometer. Nonglutinous and glutinous rice starch suspensions at $30-60^{\circ}C$, and $30-55^{\circ}C$, respectively, had no yield stress and showed dilatant flow behavior in the absence or presence of phosphate. However, flow behavior of nonglutinuous starches at $65^{\circ}C$ and glutinous starch at $60^{\circ}C$ was pseudopalastic. Flow activation energies for rice starch suspensions were 0.88-1.45 kcal/mole at $30-50^{\circ}C$ and about 45-73 kcal/mole $60-65^{\circ}C$. Flow activation energy in the presence of phosphate was 90-182 kcal/mole at $60-65^{\circ}C$. Akibare starch had the highest activation energy, and glutinous starch the lowest.

Structure, Thermal Stability, and Mechanical Modulus of Polylactide Nanocomposites Reinforced with Organically Modified Layered Silicate

김일환,정영규,Kim, Il-Hwan,Jeong, Young Gyu The Korean Fiber Society 2012 한국섬유공학회지 Vol.49 No.4

We have manufactured polylactide (PLA) nanocomposites reinforced with layered silicates by the melt compounding method and have investigated their structure, thermal stability under oxygen or nitrogen atmosphere, and temperature-dependent mechanical modulus by adopting XRD, SEM, TGA, and DMA. Octadecylammonium-modified montmorillonite (organo-MMT) is used as an organically modified layered silicate and, for comparison, sodium montmorillonite (Na-MMT) is adopted as a purely inorganic layered silicate. X-ray diffraction patterns and SEM images confirm that the organo-MMT is intercalated and dispersed homogenously in the PLA matrix, whereas Na-MMT remains unchanged by forming agglomerated domains in the matrix. Unlike the PLA/Na-MMT nanocomposites, the thermal stability of PLA/organo-MMT nanocomposites is found to be substantially improved with the increment of organo-MMT content, especially under oxygen gas atmosphere. In addition, the mechanical modulus of PLA/organo-MMT nanocomposites in the glassy state are highly improved.

Micro Mechatronics 관련 기술의 최근 연구동향

김일환,정광조,Kim, Il-Hwan,Jeong, Gwang-Jo 재료연구소 1994 機械와 材料 Vol.6 No.1

생리학적 수법을 이용한 로봇 핸드의 제어기술

김일환,정광조,Kim, Il-Hwan,Jeong, Gwang-Jo 재료연구소 1993 機械와 材料 Vol.5 No.3

저온검출기의 열전도 연구

김일환,이민규,김용함,Kim, Il-Hwan,Lee, Min-Kyu,Kim, Yong-Hamb 한국초전도학회 2010 Progress in superconductivity Vol.12 No.1

Low temperature micro-calorimeters have been employed in the field of high resolution alpha spectrometers. These alpha detectors typically consist of a superconducting or metal absorber and a temperature sensor. The temperature sensor can be a transition edge sensor (TES), a metallic magnetic calorimeter (MMC) or other low temperature detectors for an accurate measurement of temperature change due to an alpha particle absorption. We report a recent study of the heat flow between a replaceable absorber and a temperature sensor. A piece of gold foil in $2.4{\times}2.7{\times}0.03\;mm^3$ is used as an absorber. A $40\;{\mu}m$ diameter Au:Er paramagnetic sensor is attached to another small piece of gold foil in $400{\times}200{\times}30\;{\mu}m^3$ to serve as the temperature sensor. This sensor assembly, Au:Er and gold foil, is placed on a miniature SQUID susceptometer in a gradiometric configuration. The thermal connection between the absorber and the sensor was made with three gold bonding wires. The measured thermal conductance shows a linear dependence to the temperature. The values are in a good agreement with Wiedemann-Franz type thermal conductance of the gold wires.

피치제어형 가변속 풍력터빈 시스템의 시뮬레이션 모델링과 해석

김일환,강경보,Kim, Eel-Hwan,Kang, Geong-Bo 한국조명전기설비학회 2005 조명·전기설비학회논문지 Vol.19 No.2

본 논문에서는 Psim프로그램을 이용하여 가변속 풍력터빈 시스템의 시뮬레이션 모델링과 해석을 수행하였다. 시뮬레이션에서는 제주 행원 풍력발전 단지에 설치되어 운영되고 있는 Vestas V47 660[kW] 시스템을 모델로 하여, 바람 모델, 블레이드 모델, 피치 제어모델과 계통선에 연계된 발전기를 모델링 하였다. 풍속의 변화에 따라 원하는 출력을 얻을 수 있도록 피치각 제어를 수행하여 정격풍속 이하에서는 최대 출력이 발생하도록 하고, 정격풍속 이상에서는 회전자 속도를 일정하게 운전하여 정격출력을 유지할 수 있도록 제어하였다. 제안한 해석방법의 타당성을 검증하기 위하여 풍속변화에 따른 모델 시스템의 실측출력 데이터와 시뮬레이션 결과 값을 서로 비교 검증하였으며, 이 결과 서로 잘 일치함을 알 수 있었다. This paper presents the simulation modeling and analysis of variable wind speed turbine system(VWTS) using Psim program In the simulation, using the Vestas V47 VWTS located in Hangwon wind farm in Jeju-Do as a model, wind model, blade model, pitch control model and grided connected generator are modeled. The VWTS is controlled by the optimal pitch angle for maximum output power under the rated wind speed and for the rated output power over the rated wind speed. To verify the effectiveness of proposed method, simulation results are compared with the actual data from the model system According to the comparison of these results, this method shows excellent performance. So it is very useful for understanding and applications of wind power control system.

Total Micrografting Hair Transplantation Using a New Hair Implanter

김일환,Yung Chul Kye ( Il Hwan Kim ) 대한피부과학회 1997 Annals of Dermatology Vol.9 No.3

Background: Hair transplantation is a continuously evolving era towards a more natural style and micrografting in greater quantities is becoming an unmistakable trend. Objective: A rapid, simple method to make a micrograft implanter with low cost and a case of total micrografting using this new hair implanter are presented. Methods: We devised a simple method to make a micrograft hair implanter using a spinal tapping needle and did total micrografting with this device 3 times on 1 patient. Results: Cosmetically, hair transplantation using our device produces hair that is slightly less dense in a normal individual. However, our technique gives a good balance in distribution of hair with no scarring which contribute to a natural style appearance. Conclusion: Total Micrografting with our new implanter produces a natural appearance without the artificial look and scars typical of the minigrafts or punch grafts in Koreans. So we consider this device as a another alternative device in hair transplantation. (Ann Dermatol 9:(3) 177-181, 1997).