• 한국ITS학회 논문지
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• 제9권5호
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• pp.38-48
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• 2010

이상기후는 도로교통 사고 위협요소로써 빈번하게 심각한 영향을 주고 있다. 특히, 도로교통에서 기상변화 또는 재해에 의한 영향은 장대교량, 터널, 사면 및 결빙 지역에서 영향이 크기 때문에 이들 지역에 대한 관심 있는 관리가 필요하며 발생할 수 있는 사고를 줄이기 위해서도 집중적인 도로 관리와 도로 기상 정보 제공 및 조기 경보, 도로 순찰, 교통통제와 같은 요소들이 필요하다. 도로의 눈과 결빙은 제설로 위험을 줄일 수는 있으나, 강풍은 피할 수 없는 요소이다. 본 연구에서는 도로 기상 정보와 기후, 재해 정보를 활용하여 국지 지역에서 안전운전을 위한 경보 정보를 설계를 하고자 한다. 극한 기상에 노출된 운전자를 위한 최상의 경보 정보 설계는 도로 상황 감시 개선, 도로 기상정보 감시, 정확한 사용자 정보전달들이 될 것이며, 또한 바람 및 재해 상황에 대한 통계, 표면 조건 통계, 차종 및 차종에 따른 바람에 의한 사고 통계와 조기 경보 정책과 교육들도 이를 위해서는 수반되어야 할 요소들이다.

• 한국전산유체공학회지
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• 제19권2호
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• pp.66-71
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• 2014

Aerodynamic design of a vehicle has very important meaning on the fuel economy, dynamic stability and the noise & vibration of a moving vehicle. In this study, the correlation of aerodynamic effect between two model vehicles moving inline on a road was studied with the basic SAE model vehicle. Drag and lift are two main physical forces acting on the vehicle and both of them directly effect on the fuel economy and driving stability of the vehicle. For the research, the distance between two vehicles is varied from 5m to 30m at the fixed vehicle speed, 100km/h and the side-wind was assumed to be zero. The main issue for this numerical research is on the understanding of the interaction forces; lift and drag between two vehicles formed inline. From the study, it was found that as the distance between two vehicles is closer, the drag force acting on both the front and rear vehicle decreases and the lift force has same trend for both vehicle. As the distance(D) is 5m, the drag of the front vehicle reduced 7.4% but 28.5% for the rear-side vehicle. As the distance is 30m, the drag of the rear vehicle is still reduced to 22% compared to the single driving.

• 한국산학기술학회논문지
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• 제14권9호
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• pp.4124-4129
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• 2013

본 연구는 무한궤도와 엔진 및 유압장치를 두어서 독립적으로 구동할 수 있는 탈곡기를 3차원 설계후 시제품을 제작하는 데 목적을 두었다. 탈곡기의 기능을 충실히 수행하기 위해서 탈곡통에 칼날을 나선형으로 배치하여 탈곡성능이 향상되게 하였다. 또한 뒤쪽에 배출구를 두어서 잔여부산물들이 적채되는 기존의 탈곡기 문제를 해결하였다. 부산물들이 콩과 섞여서 배출되지 않게 하려고 경사진 벨트를 내부에 두어 부산물들만 직접 송풍하도록 설계하였다. 완전히 정선된 콩만이 스크류 축을 통해서 통에 적재되면 송풍팬을 통해 배출관 파이프를 따라 이동하여 최종적으로 포장자루에 바로 담을 수 있도록 편의성을 고려하여 설계하였다. 본 독립구동방식의 콩 탈곡기 시스템은 산학협력을 통하여 국산화한 기술로서 국내 최초의 독립구동 방식의 자주형 콩 탈곡기 시스템이다.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제3B권1호
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• pp.10-15
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• 2003

This paper presents the digital computer performance evaluations of the three-phase self-excited induction generator (SEIG) driven by the variable speed prime mover such as the wind turbine using the nodal admittance approach steady-state frequency domain analysis with the experimental results. The three-phase SEIG setup is implemented for small-scale rural renewable energy utilizations. The experimental performance results give a good agreement with those ones obtained from the digital computer simulation. Furthermore, a feedback closed-loop voltage regulation of the three-phase SEIG as a power conditioner which is driven by a variable speed prime mover employing the static VAR compensator (SVC) circuit composed of the thyristor phase controlled reactor (TCR) and the thyristor switched capacitor(TSC) is designed and considered herein for the wind-turbine driven the power conditioner. To validate the effectiveness of the SVC-based voltage regulator of the terminal voltage of the three-phase SEIG, an inductive load parameter disturbances in stand-alone are applied and characterized in this paper. In the stand-alone power utilization system, the terminal voltage response and thyristor triggering angle response of the TCR are plotted graphically. The simulation and the experimental results prove the effectiveness and validity of the proposed SVC which is controlled by the Pl controller in terms of fast response and high performances of the three-phase SEIG driven directly by the rural renewable energy utilization like a variable-speed prime mover.

• International Journal of Advanced Culture Technology
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• 제3권1호
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• pp.90-100
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• 2015

Green technologies such as renewable energy resources, Electric Vehicles and Plug-in Hybrid Electric Vehicles (EVs/PHEVs), electric locomotives, etc. are continually increasing at the existing power network especially distribution levels, which are Medium Voltage (MV) and Low Voltage (LV). It can be noted that the increasing level of green technologies is driven by the reduction emission policies of carbon dioxide ($CO_2$). The green technologies can affect the quality of power, and hence its impacts of are analysed. In practical, the environment such as wind, solar irradiation, temperature etc. are uncontrollable, and therefore the output power of renewable energy in that area can be varied. Moreover, the technology of the EVs/PHEVs is still developed in order to improve the performance of supply and driving systems. This means that these developed can cause harmonic distortion as the control system is mostly used power electronics. Therefore, this paper aims to analyse the voltage variation and harmonic distortion in distribution power network in urban area in Europe due to the combination between wind turbine, hydro turbine, photovoltaic (PV) system and EVs/PHEVs. More realistic penetration levels of SSDGs and EVs/PHEVs as forecasted for 2020 is used to analyse. The dynamic load demands are also taken into account. In order to ensure the accurate of simulation results, the practical parameters of distribution system are used and the international standards such as Institute of Electrical and Electronics Engineers (IEEE) standards are also complied. The suggestion solutions are also presented. The MATLAB/Simulink software is chosen as it can support complicate modelling and analysis.

• 전기학회논문지
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• 제67권4호
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• pp.512-521
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• 2018

Islands that is far away from onshore have used internal-combustion engine driving alternators to secure electric power. However, with Paris convention on climate change, there is a growing interest in eco-friendly energy independent island that replaces microgrid(MG) consisting of photovoltaic, wind power, and energy storage system with alternators for internal combustion engines. And also, national emission trading has been implemented, and the price of certified emission reduction(CER) has a influence on system marginal price(SMP). Because, the low cost generation source decides SMP when CER price is low, while the more expensive generation source decides SMP when CER price is high. Therefore, the increasing of CER price has a strong influence on the annualized return of MG independent power producer. Moreover, the fixed RPS price is implemented from 2017, which the increasing of CER price under the fixed RPS price or the variable RPS price affects annualized return differently. In this paper, the annualized return according to CER price is analyzed for large, middle, and small scaled islands, the effect of CER price on the annualized return was confirmed.

• 설비공학논문집
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• 제9권2호
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• pp.153-162
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• 1997

In this study, the wet surface heat transfer coefficients and friction factors of the heat exchanger with slit-wavy fin were measured. Four sample cores of two or three row with fins of 12 fpi or 16 fpi were tested. Tests were conducted in a closed loop wind tunnel, where the heat exchanger was mounted at 45 degree inclination angle. The wet surface heat transfer coefficient was reduced following the procedure given in ARI 420-81. During the course, new definitions of the $\varepsilon$-NTU applicable to enthalpy driving system were introduced. The wet surface heat transfer coefficients were approximately equal to the dry surface values. However, the friction factors were approximately 120% to 170% higher than those of the dry surface. Both the heat transfer coefficient and the friction factor of the wet surface increased as the relative humidity increased, fin pitch decreased, and the number of row decreased, although the difference was not large.

• 한국생산제조학회지
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• 제21권2호
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• pp.305-310
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• 2012

Planetary gear box is a power transmitter having very high gear ratio in compact volume. The planetary step-down gear box converts high speed and low torque into low speed and high torque, which is widely used in constructional and industrial machinery field. And, the planetary step-up gear box does vice versa working, which is used as main gear box of large sized wind mill system. The large sized planetary gear box must be performed the normal-opposite rotation test as a its durability test for achieving the reliability. The large sized planetary gear box is composed by triple gear trains of sun gear, carrier, and ring gear. If input power is supplied into one of them and the other is fixed, and then another becomes the output part. In this paper, we designed a new test equipment which can do rapid normal and opposite rotational change with only small displacement by supplying test power using the above rotation (driving) characteristics and hydraulic cylinder and link, and also compared and analyzed with existing method through various experiments.

• 한국군사과학기술학회지
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• 제18권5호
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• pp.498-509
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• 2015

The existing mobile antenna networks in the military use have been operated by the manual pointing between two antennas. The work presented here describes the study of ATPC(Automatic Tracking and Pointing Control) system between facing antennas and the related tracking and pointing performances. This system is able to automatically track the maximum RSSI(Received Signal Strength Indication) value from the source's RF(Radio Frequency) signal and then control for maintaining the LOS(Line of Sight) between two antennas. The system has three major units; the driving unit consisting of motors, harmonic drives and encoders, the sensor unit with a GPS(Global Positioning System) and AHRS(Attitude and Heading Reference System) and the control unit regulating all the tracking and pointing events. By using PI(Proportional and Integral) controller, this system is able to properly track and point the other antenna under the external disturbance like the wind load. Both the simulation and the experimental works have been successively carried out to prove the performances of the system.

• 한국전기전자재료학회논문지
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• 제26권4호
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• pp.257-263
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• 2013

In this paper, Solar, Wind, fuel cell used in a Power conversion devices and industrial inverter motor to increase the efficiency of energy consumption, which is a core part of high-efficiency, high-voltage Trench Gate Field Stop IGBT was studied. For this purpose Planar type NPT IGBT and Planar type Field Stop IGBT have designed a basic structure designed to Trench Gate Field Stop IGBT based on the completed structure by analyzing the energy consumption of electrical characteristics, efficiency is a key part, high-efficiency and high-voltage inverter for industry regarding the optimization design for Trench Gate Field Stop IGBT.