• 한국정보전자통신기술학회논문지
• /
• 제6권3호
• /
• pp.168-173
• /
• 2013

본 연구는 IGBT(Insulated Gate Bipolar Transistor)의 전기적 특성을 향상시키기 위해 새로운 구조의 IGBT를 제안하였다. 첫 번째 구조는 기존 IGBT 구조의 P-베이스 영역 우측 부분에 N+영역을 추가한 방법으로 기존 구조에 비해 빠른 Turn-off 시간과 낮은 전도 손실을 갖는 구조이다. 또한, 두 번째 구조는 게이트 우측 하단에 P+를 형성함으로써 Latching 전류를 향상시킨 구조이다. 시뮬레이션 결과 제안된 첫 번째 구조는 빠른 Turn-off 시간(3.4us), 낮은 순방향 전압강하(3.08V)의 특성을 보였으며, 두 번째 구조는 높은 Latching 전류(369A/?? ) 특성을 보였다. 따라서 본 논문은 제안된 두 가지의 구조를 하나로 결합한 구조로써 기존 IGBT보다 향상된 특성을 시뮬레이션을 통하여 확인하였다.

• 한국전기전자재료학회논문지
• /
• 제26권4호
• /
• pp.271-274
• /
• 2013

Power Metal Oxide Semiconductor Field Effect Transistor's (MOSFETs) are well known for superior switching speed, and they require very little gate drive power because of the insulated gate. In these respects, power MOSFETs approach the characteristics of an "ideal switch". The main drawback is on-resistance RDS(on) and its strong positive temperature coefficient. While this process has been driven by market place competition with operating parameters determined by products, manufacturing technology innovations that have not necessarily followed such a consistent path have enabled it. This treatise briefly examines metal oxide semiconductor (MOS) device characteristics and elucidates important future issues which semiconductor technologists face as they attempt to continue the rate of progress to the identified terminus of the technology shrink path in about 2020. We could find at the electrical property as variation p base dose. Ultimately, its ON state voltage drop was enhanced also shrink chip size. To obtain an optimized parameter and design, we have simulated over 500 V Field ring using 8 Field rings. Field ring width was $3{\mu}m$ and P base dose was $1e15cm^2$. Also the numerical multiple $2.52cm^2$ was obtained which indicates the doping limit of the original device. We have simulated diffusion condition was split from $1,150^{\circ}C$ to $1,200^{\circ}C$. And then $1,150^{\circ}C$ diffusion time was best condition for break down voltage.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2005년도 춘계 학술발표회 논문집
• /
• pp.401-408
• /
• 2005

Recently shield TBM tunnellings are being applied to subway construction in Korean cities. Generally these kinds of tunnellings have the problems in the stability of ground such as subsidence because urban subway is constructed in the shallow depth. A sinkhole occurred on the road just above the tunnel during tunneling in Kwangju, so a survey for upper layer of the tunnel was needed. But conventional Ground Probing Radar can't be applicable due to the presence of steel-mesh screen in the shield segment, so no existent geophysical method is applicable in this site. Because the outer surface of each shield segment is electrically insulated, dipole-dipole resistivity method which is popular in engineering site investigation, was tried to this survey for the first time. Specially manufactured flexible ring-type electrodes were installed into the grouting holes at an interval of 2.4 m on the ceiling. The K-Ohm II system which has been developed by KIGAM and tested successfully in many sites, was used in this site. The system consists of 1000Volt-1Ampere constant-current transmitter, optically isolated 24 bit sigma-delta A/D conversion receiver - maximum 12 channel simultaneous measurements, and graphical automatic acquisition software for easy data quality check in real time. Borehole camera logging with circular white LED lighting was also done to investigate the state of the layer. Measured resistivity data lack of some stations due to failing opening lids of holes, shows general high-low trend well. The dipole-dipole resistivity inversion results discriminate (1) one approximately 4 meter diameter cavity (grouted but incompletely hardened, so low resistivity - less than $30{\Omega}m$), (2) weak zone (100-200${\Omega}m$), and (3) hard zone (high resistivity - more than 1000${\Omega}m$) very well for the distance of 320 meters. The 2-D inversion neglects slight absolute 3-D effect, but we can get satisfactory and useful information. Acquired resistivity section and video tapes by borehole camera logging will be reserved and reused if some problem occurs in this site in the future.

• 조명전기설비학회논문지
• /
• 제29권8호
• /
• pp.98-103
• /
• 2015

Power plant is that very high reliability when industrial and economic impact on the overall electric power system is required, it is essential to improve the reliability, especially the fault prediction diagnosis. Since an accident caused by the partial discharge in the power plant is above state has a faster response characteristic than the other indications in the case of any, the partial discharge generated in the power plant immediately detect the deterioration of insulation due to the accident of the power plant and the non-drawn It should prevent or reduce. Partial Discharge Measuring Systems for UHV SF6 Gas Insulated Switchgear and power transformer on site installed has some probability of abnormal recognition in case of non-flexible deal with on site noise. Many methode to eliminate these kinds of noises, UHF Detection System is chosen as purchase description in Korea, but this system having a bandwidth between 500MHz 1.5GHz wide band. Initial install periods(about 20 years ago), this band had no strong signal source, but in these days this wide band have strong signals, such as LTE. So, module described in this paper is designed as simultaneously use with wide and narrow band for solve this noise problem, and introduce this system.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 제38회 하계학술대회
• /
• pp.2032-2033
• /
• 2007

There has been increasing interests of condition monitoring and diagnosis for electric equipment, which lead to the development of this system domestic and abroad. In the past, operators' interest was how to quickly repair and restore the electric equipments after failure. But, due to the North American Blackout in 2003 and the aging of equipments, users have paid attention to the condition based monitoring of electric equipment to prevent a fault like outrage. GIS-PDS("GIS Preventive and Diagnosis System") requiresa large amount of measurement data with timeliness for monitoring and analysis of real-time state of GIS(Gas Insulated Switchgear). We developed the timeliness-guaranteed communication device for GIS-PDS.

• KIEAE Journal
• /
• 제7권5호
• /
• pp.93-98
• /
• 2007

Effort has been performed for latest 20 years to improve resident's comfort and indoor environment in building. And interest and effort to improve indoor air environment among various indoor environment elements have continuously increased since 1990s, because it is examined scientifically that various contaminants generated indoor affect human body. Specially, indoor air contaminants generated from apartments are those exhausted from resident's indoor environment, closing materials and household. Indoor air environment in buildings is different according to pollution degree, existence availability of pollution source, ventilation amount, and meteorology. It is known that other contaminants more than about 900 kinds generate according to a kind of work or action in a room. Specially, nowadays buildings are well insulated and confidentiality-centered for environment protection and economical side. So indoor air contaminants are generated from indoor air pollution sauces of unprepared ventilation, human body carbon dioxide emissions, and various building materials. when these are accumulated in long term human body, it is harmful to resident's health, but awareness for this is very insufficient. Because bedroom is space that people inhabit for a long time by unconscious state and indoor environment occupies important part for resident's health and quality of life at sleep, the actual condition of air quality is investigated, improvement countermeasure is considered, and ventilation amount is analyzed. In this study, putting case that the most longest stayed time is sleeping time when people inhabit in the apartment, the air quality according to volume of bedroom space at sleep was measured and analyzed, and the data acquired will be the basis for improvement on this.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2009년도 춘계학술대회
• /
• pp.845-848
• /
• 2009

전력용반도체(Power Management IC)는 전력의 변환이나 제어용으로 최적화되어 있는 전력장치용 반도체 소자로서 전자기기에 들어오는 전력을 그 전자기기에 맞게 변경하는 역할을 하며, 일반 반도체에 비해서 고내압화, 큰 전류화, 고주파수화 되어 있다. 전력용반도체는 전기가 쓰이는 제품에는 다 들어가며, 자동차, 공업제품, 컴퓨터와 주변기기, 통신, 가전제품, 모바일 기술, 대체 에너지 등에 대한 수요 증가가 시장의 성장을 촉진한다. 전력용반도체 개발을 통해 대일무역적자 해소 기여, 취약한 비메모리 산업의 육성을 통한 반도체산업의 균형발전, 신성장동력 창출을 통한 미래 경제발전을 도모할 수 있다. 본 고에서는 반도체 부문의 미래 유망품목인 전력용반도체의 필요성 및 중요성, 시장현황 및 전망을 중심으로 살펴보고 결론에서 정책적 시사점을 도출하고자 한다.

• Structural Engineering and Mechanics
• /
• 제85권1호
• /
• pp.105-118
• /
• 2023

The present work is an attempt to develop a simple and accurate finite element formulation for the assessment of thermal shock/thermally induced vibrations in pretwisted and tapered functionally graded material thin (FGM) blades obtained from Voigt and local representative volume elements (LRVE) homogenization models, based on neutral surface approach. The neutral surface of the FGM blade does not coincide with its mid-surface. A finite element model (FEM) is developed using first-order shear deformation theory (FSDT) and the FGM turbine blade is modelled according to the shallow shell theory. The top and the bottom layers of the FGM blade are made of pure ceramic and pure metal, respectively and temperature-dependent material properties are functionally graded in the thickness direction, the position of the neutral surface also depends on the temperature. The material properties are estimated according to two different homogenization models viz., Voigt or LRVE. The top layer of the FGM blade is subjected to high temperature and the bottom surface is either thermally insulated or kept at room temperature. The solution of the nonlinear profile of the temperature in the thickness direction is obtained from the Fourier law of heat conduction in the unsteady state. The results obtained from the present FEM are compared with the benchmark examples. Next, the effect of angle of twist, intensity of thermal shock, variable chord and span and volume fraction index on the transient response due to thermal shock obtained from the two homogenization models viz., Voigt and LRVE scheme is investigated. It is shown that there can be a significant difference in the transient response calculated by the two homogenization models for a particular set of material and geometric parameters.

• Transactions on Electrical and Electronic Materials
• /
• 제14권4호
• /
• pp.211-215
• /
• 2013

Partial discharge diagnosis techniques using ultra high frequencies do not affect load movement, because there is no interruption of power. Consequently, these techniques are popular among the prevention diagnosis methods. For the first time, this measurement technique has been applied to the GIS, and has been tested by applying an extra high voltage switchboard. This particular technique makes it easy to measure in the live state, and is not affected by the noise generated by analyzing the causes of faults ? thereby making risk analysis possible. It is reported that the analysis data and the evaluation of the risk level are improved, especially for poor location, and that the measurement of Ultra high frequency (UHF) partial discharge of the real live wire in industrial switchgear is spectacular. Partial discharge diagnosis techniques by using the Ultra High Frequency sensor have been recently highlighted, and it is verified by applying them to the GIS. This has become one of the new and various power equipment techniques. Diagnosis using a UHF sensor is easy to measure, and waveform analysis is already standardized, due to numerous past case experiments. This technique is currently active in research and development, and commercialization is becoming a reality. Another aspect of this technique is that it can determine the occurrences and types of partial discharge, by the application diagnosis for live wire of ultra high voltage switchgear. Measured data by using the UHF partial discharge techniques for ultra high voltage switchgear was obtained from 200 places in Gumi, Yeosu, Taiwan and China's semiconductor plants, and also the partial discharge signals at 15 other places were found. It was confirmed that the partial discharge signal was destroyed by improving the work of junction bolt tightening check, and the cable head reinforcement insulation at 8 places with a possibility for preventing the interruption of service. Also, it was confirmed that the UHF partial discharge measurement techniques are also a prevention diagnosis method in actual industrial sites. The measured field data and the usage of the research for risk assessment techniques of the live wire status of power equipment make a valuable database for future improvements.

• 한국식품과학회지
• /
• 제26권3호
• /
• pp.199-203
• /
• 1994

외기의 온도를 감지하여 김치의 품온을 유추함으로써 사계절에 관계없이 일정한 김장 김치맛을 감도록 하면서 소비자의 기호도를 고려하여 풋맛(key I), 김장맛(key II), 익은맛(key III)에 가까운 김치를 조기에 숙성시켜 장기간 저장할 수 있는 냉장고용 자동 제어시스템을 개발하였다. 이때 온도에 대한 micom의 디지털 출력값과의 상관관계식은 $T(^{\circ}C)$=-2.1516D+61.2037이었고 R은 0.9759로 나타났다. 자동제어시스템에 의한 김치 발효효과를 조사한 결과 key I에서는 식염농도 2%, 3% 및 5%의 경우 김치의 적숙기에 해당하는 pH4.5. 산도 0.6%에 이르는데 각각 약 $3{\sim}4$일, $4{\sim}5$일 및 $11{\sim}12$일, key II에서는 약 $2{\sim}3$일, $3{\sim}4$일 및 $10{\sim}11$일 그리고 key III에서는 약 2일, 3일 및 $9{\sim}10$일이 소요되었다. 그리고 발효 및 저장선택 3단계 key에서 저장효과는 모두 14일까지 식이 가능한 수준의 pH 및 산도범위로 유지되었고 pH 및 산도, 총균수 및 젖산균수, 환원당 함량의 변화 결과로 보아 저장효과가 어느정도 더 연장될 것으로 나타났다. 한편, 김치의 관능평가에서도 기호도면에서 뚜렷한 차이를 보였는데 특히 3% 시험구가 관능적으로 가장 좋았고 2%, 5% 순으로 나타났다. 더욱이 5% 시험구는 발효도 느리게 일어나고 관능적인 면에서도 바람직하지 못한 것으로 나타났다.