• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.947_948
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• 2009

In an attempt to minimize the air pollution caused by CO2, $NO_X$x, and $SO_X$ and the fuel cost, the auto industries and researchers recently are looking into replacing the diesel and gasoline cars with hybrid electric vehicles, plug-in electric vehicles, or battery powered electrical vehicles. This paper reports the technical status of the primary components such as batteries, motors, power control units and auxiliary parts to be used for electric vehicles.

• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.189-191
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• 2007

본 연구에서는 고분자전해질연료전지(PEFC)를 이용하여 보조전 원용으로 사용할 수 있는 계통연계 연료전지 시스템을 개발하였다. 또한 본 연구에서 DSP(Digital Signal Processor)를 이용한 계통연계형 전력변환장치(PCS, Power Conditioning System)와 시스템 제어기의 개발도 병행하여 수행되었다. 개발된 1kW급 보조전원용 연료전지 시스템은 다양한 조건에서의 스택 성능 실험 및 BOP 연계 시험을 통해 최적의 운전점을 도출할 수 있었으며, PID(Proportional, Integral, Differential) 운전제어 방식을 통하여 시스템의 안정적인 운전 특성을 확보하였다. 향후 본 시스템은 계통연계용은 물론 독립전원용으로도 사용이 가능할 수 있도록 전력변환장치를 설계하여 적용할 예정이다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.294-297
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• 2014

A Shipboard power system consists of three or four diesel generator sets connected to a grid. In case of dual fuel diesel generator sets employed LNG ship as a prime mover, large amounts of electricity are required for electric propulsion, auxiliary machinery and accommodation facilities. The electrical connection between generators through a network, torsional vibration can lead power swings. In this paper, the influence on the network by the torsional vibration of diesel generator sets in grid operation were studied. The torsional vibration characteristics were investigated and analyzed through theoretical analysis and the vibration measurement and the results were presented.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.209-212
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• 2008

본 논문에서는 연료전지자동차의 저전압 배터리 충 방전을 위한 새로운 3상 양방향 DC-DC 컨버터를 제안한다. 12V 저전압측의 높은 전류정격 때문에 기존의 풀브리지 방식으로는 적절한 스위치의 선정이 어렵지만 제안한 3상의 전류분배로 스위치의 선정과 변압기의 제작이 용이하다. 그리고 제안한 변압기 결선으로 턴비가 작아져 누설인덕턴스가 작아진다. 또한 비대칭 PWM에 의한 모든 스위치의 ZVS 턴온과 저전압 측에서는 동기정류 방식을 적용하여 효율을 상승시켰다. 제안하는 컨버터의 동작원리를 기술하고 3.5kW 시작품을 제작하여 실험을 통해 본 방식의 타당성을 검증한다.

• Proceedings of the KSR Conference
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• 2002.10b
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• pp.876-883
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• 2002

Electric vehicle body has to be subjected to uniform load and requires auxiliary equipment such as air pipe and electric wire pipe. Especially, the cross beam supports the weight of passenger and electrical equipments. a lightweight vehicle body is salutary to save operating costs and fuel consumption. Therefore this study is to perform the size and the shape optimization of crossbeam fur electric vehicle using the method of topology optimization to introduce the concept of homogenization based on optimality criteria method which is efficient for the problem having the number of design variables and a few boundary condition. this provides the method to determine the optimum position and shape of circular hole in the cross beam and then can achieve the optimal design to reduce weight.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.445-450
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• 1998

In this paper, a robust nonlinear prediction-type controller (RNPC) is developed for the continuous time nonlinear system whose control objective is composed of system output and its desired value. The basic control law of RNPC is derived such that the future response of the system is first predicted by appropriate functional expansions and the control law minimizing the difference between the predicted and desired responses is then calculated. RNPC which involves two controls, i.e., the auxiliary and robust controls into the basic control, shows the stable closed loop dynamics of nonlinear system of any relative degree and provides the robustness to the nonlinear system with parameter/modeling uncertainty. Simulation tests for the position control of a two-link rigid body manipulator confirm the performance improvement and the robustness of RNPC.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.12 no.1
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• pp.2-11
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• 1983

The solar energy retention rate of a flat plate collector can be increased by increasing water flow rate through the collector which also increases the pumping energy incurred in obtaining that solar energy. The problem of optimal flow rate is formulated to fit within the framework of pontryagin's maximum principle and with a few simplifying assumptions, an optimal solution that can be easily implemented is obtaincd, The optimal solution is used in the simulation of a solar heating system using actual climatological data and the results are compared with that of on-off control. The result that not only the object function but, In some cases, also the solar energy retention rate the collector is increased. In is also found that the optimal control gets more advantageous as the solar insolation level gets lower, and also as tile cost of auxiliary heating fuel gets higher.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.15 no.3
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• pp.292-298
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• 1986

The new f-chart capable of estimating long-term thermal performance of solar space and water heating systems was developed. The system comprise a flat plate solar collector, heat exchanger, storage tank filled with water, auxiliary fuel fired heater, and a house structure. The information obtained from many simulations of solar heating systems has been used to develop this f-chart. Actual hourly meteorological data collected in Seoul, Daejeon, Kwangju and Daegu, Korea from 1979 to 1983 have been utilized in these simulations. The new f-equation is as follows: $$f=1.034Y_{-}0.0968X_{-}0.2235Y^2+0.0043X^2+0.0144Y^3$$. The system performance estimates obtained from the developed f-chart are in close agreement with the results of experiment.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.3
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• pp.27-39
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• 2009

The main objective of this study is to investigate the characteristics of combustion by analyzing fuel gases from a combustion equipment with various combustion conditions for refuse-derived fuels (RDFs). CO gas is a parameter for indicating of incomplete combustion during a combustion process. The lowest CO gas was produced when the experiment conditions were m=2 under air-fuel condition and $800^{\circ}C$. $CO_2$ gas is a final product after complete combustions. The highest amount of $CO_2$ gas was produced when the experiment conditions were m=2 under air-fuel condition and $800^{\circ}C$. The highest level of $SO_2$ gas was produced in S.1 sample containing the highest sulfur. The highest level of NOx gas was produced in S.1 sample with the highest nitrogen content and air-fuel condition of m=2 under temperature of $800^{\circ}C$. HCl gas that is generated by reacting with metals catalyst through oxygen catalyst reaction during combustion process is a precursor of dioxin formation. The higher level of HCl gas was produced in the sample with higher chlorine content. The lowest level of HCl gas was produced when the experiment conditions were air-fuel condition of m=2 and $800^{\circ}C$. The lowest level of $NH_3$ gas was generated when the experiment condition was m=2 under air-fuel condition and after 3 minutes. Air-fuel condition is more important to create $NH_3$ gas than operating temperatures. Higher level of $H_2S$ gas was generated in S.1 sample with the higher sulfur content and was created in RDFs that contain higher mixture ratios of sewage sludge and food wastes. A result of combustion, gases and gases levels from the combustion of S.1 and S.2 were very similar to the combustion of a stone coal. As results of this research, when evaluating the feasibility of the RDFs, the RDFs could be used as auxiliary and main fuels.

• Journal of Environmental Science International
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• v.25 no.2
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• pp.239-246
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• 2016

This study aims to analyze region-specific trends in changing greenhouse gas emissions in incineration plants of local government where waste heat generated during incineration are reused for the recent five years (2009 to 2013). The greenhouse gas generated from the incineration plants is largely $CO_2$ with a small amount of $CH_4$ and $N_2O$. Most of the incineration plants operated by local government produce steam with waste heat generated from incineration to produce electricity or reuse it for hot water/heating and resident convenience. And steam in some industrial complexes is supplied to companies who require it for obtaining resources for local government or incineration plants. All incineration plants, research targets of this study, are using LNG or diesel fuel as auxiliary fuel for incinerating wastes and some of the facilities are using LFG(Landfill Gas). The calculation of greenhouse gas generated during waste incineration was according to the Local Government's Greenhouse Emissions Calculation Guideline. As a result of calculation, the total amount of greenhouse gas released from all incineration plants for five years was about $3,174,000tCO_2eq$. To look at it by year, the biggest amount was about $877,000tCO_2eq$ in 2013. To look at it by region, Gyeonggido showed the biggest amount (about $163,000tCO_2eq$ annually) and the greenhouse gas emissions per capita was the highest in Ulsan Metropolitan City(about $154kCO_2eq$ annually). As a result of greenhouse gas emissions calculation, some incineration plants showed more emissions by heat recovery than by incineration, which rather reduced the total amount of greenhouse gas emissions. For more accurate calculation of greenhouse gas emissions in the future, input data management system needs to be improved.