• 한국자동차공학회논문집
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• 제16권6호
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• pp.65-73
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• 2008

The purpose of this study is development of universal engine model for integrated Hybrid Electric Vehicle (HEV) simulator and a optimization of engine model. The engine model of this study is based on the MATLAB Simulink for universal and include engine fuel economy technologies for HEV. Various engine fuel economy technologies for HEV is estimated by commercial engine 1-D simulation program - WAVE. And, the 1-D simulation model of base version is compared with engine experiment result. The analyzed engine technologies with 1-D simulation are Dual-CVVT, Atkinson-Cycle and Cylinder-Deactivation System. There are improvement of fuel economy and power performance with Dual-CVVT model at part load and full load, pumping loss reduction with Cylinder-Deactivation System at idle and regeneration. Each estimated technologies are analyzed by 1-D simulation on all operation region for base data to converse simulink. The simulink based engine model maintains a signal with ECU for determination of engine operation point.

• 한국수소및신에너지학회논문집
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• 제23권5호
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• pp.484-492
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• 2012

The TMS(Thermal Management System) heater in a fuel cell vehicle has been developed to prevent a decline of fuel cell durability and cold start durability. Main functions of the COD(Cathode Oxygen Depletion) heater are depletion of oxygen in a cathode as heat energy and consumption of electric power for rapid warming up of a fuel cell stack. This paper covers subjects including the design specification of a heater, heater controller for detection of overheat and reliability assessment including coolant pressure cycle test of a heater. To verify the design concept, burst pressure and deformation analysis of plastic housing were carried out. Also, temperature distribution analysis of heater surface and coolant inside of housing were carried out to verify the design concept. By designing the plastic housing instead of a steel housing, the 30% weight lightening and 50% cost reduction were attained. A module-based design of a TMS system including a heater or reducing the watt density of a heater is a problem to be solved in the near future work.

• 한국기계가공학회지
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• 제19권9호
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• pp.116-121
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• 2020

In recent times, fuel economy enhancement and environmental regulation compliance have become the main topics of interest in the automobile industry. Electric vehicles are desirable alternatives to the existing cars that employ internal combustion engines. Specifically, electric vehicles are equipped with inverters, motors, and a gearbox instead of engines and transmission mechanisms. The gearbox is a key component, used to transmit power from the electric motor to the wheel. Therefore, the design of the gearbox is critical. However, most engineers design gears based only on their experience because no standards pertaining to the design factor exist, other than those for the gear ratios. To overcome this problem, the structural stabilities must be examined considering the design factors of the gears. In this study, we considered the module and number of teeth as the main factors. The constraints corresponded to the final gear ratio and fixed distance between each axle of the shafts. Moreover, a structural analysis was conducted, and the variation trend of the maximum equivalent stress against changes in the gear module and number of teeth was examined. By performing such an analysis, the structural stability in the design of a gear system could be effectively investigated.

• 디지털융복합연구
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• 제17권7호
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• pp.131-138
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• 2019

전 세계 전력 생산 에너지의 비율은 석탄이 40%, 천연가스 20%, 수력 16%, 원자력 15%, 석유 6%로 모두가 환경오염을 유발하는 에너지다. 또한 화석연료는 지구상에 자원의 편중이 심하기 때문에 가격과 공급면에서 심각한 문제를 야기한다. 이러한 문제로 화석 연료를 대체하게 될 차세대 친환경 에너지로써 태양광 에너지가 각광 받고 있다. 이에 본 연구에서는 국내 공단에 Test-Bed를 선정하여 수용가의 대응용 태양광 ESS 시스템 적용함에 있어 Peak-cut 운영을 위한 Charge Operation Plan과 Discharge Operation Plan 운영방안을 최대수요전력 감소 시뮬레이션을 통해 검증하고자 한다. 이를 위해 전력사용량이 가장 많은 11월부터 2월의 전력사용량을 선정하여 Charge/Discharge Logic을 적용했다. 본 논문에서 제시한 충전/방전 로직에 따른 시뮬레이션 결과, ESS Peak-cut 서비스 이후의 최대수요전력이 감소하였으며 Peak-target 전력의 50%로 감소함에 따라 계약전력 또한 감소함을 알 수 있다. 이를 통해 계약전력 감소는 해당 수용가의 기본 전력 값을 감소시켜, 경제적 우월성을 기대할 수 있을 뿐만 아니라 전기품질 향상 및 전력공급시스템의 안정화에도 기여할 수 있을 것으로 판단된다.

• 공업화학
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• 제23권4호
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• pp.359-366
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• 2012

아연금속-공기전지는 기존의 이차전지보다 높은 중량당 에너지 밀도, 낮은 제조단가를 가짐과 동시에 소재적으로 친환경적이다. 소형 및 중대형 전력 저장 시스템, 전기자동차, 스마트 휴대기기의 상용화에 있어 최우선시 되고 있는 것은 배터리의 충 방전 능이다. 따라서 환원 촉매의 높은 과전압, 산화 전극의 불안정성 및 비가역성, 액체 전해질 사용에 따른 여러 문제점을 해결하여야 한다. 본 총설에서는 공기극 막의 손상 방지 기술, 아연금속 전극의 구조 개선을 통한 충전효율 저하 방지 기술, 부반응 및 부동태화를 막기 위한 하이브리드 전해질 도입 등의 최근 기술적 이슈와 연구동향을 소개하고자 한다.

• 한국전기전자재료학회논문지
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• 제24권1호
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• pp.36-41
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• 2011

Medical X-ray has been brought many changes according to the rapid development of high technology. Especially, for high-voltage generator which is the most important in X-ray generation the traditional way is to use high-voltage electric transformers primarily. However, since it is large and heavy and the ripple rate of DC high-voltage applied to X-ray tube is too big, it has a disadvantage of low X-ray production efficiency. To solve these problems, the studies about high-voltage power supply are now proceeding. At present, the high-voltage generator that generates high-voltage by making high frequency using inverter control circuit consisting of semiconductor device is mainly used. High-voltage generator using inverter has advantages in the diagnosis using X-ray including high performance with short-term use, miniaturization of power supply and ripple reduction. In this study, the X-ray high-voltage device with inverter type using pulse width modulation scheme to the control of tube voltage and tube current was designed and produced. For performance evaluation of produced device, the control signal analysis, irradiation dose change and beam quality depending on the load variation of tube voltage and tube current were evaluated.

• 한국생산제조학회지
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• 제21권5호
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• pp.778-783
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• 2012

Due to the increase of oil price, the needs of the reduction of the fuel cost is rising. Therefore, necessity of hybrid vehicle that runs with engine and the electric motor is on the rise. In order to improve the performance of hybrid vehicle, many researches is carried out. Hybrid vehicles have been developed with the various layout such as serial type, parallel type, power split type, and multi-mode type. The multi-mode hybrid vehicles are designed to show the efficient driving characteristics at low speed and high speed. But the multi-mode system have the problem such as frequent clutch engagement. Frequent clutch engagement causes the shock of vehicles, and the shock inhibits the ride comfort. In this study, automation mechanism of clutch operation is proposed to mitigate the shock at engaging clutch. For this purpose, the dynamic characteristics of motor control is numerically analyzed by using Matlab/Simulink.

• Journal of Power Electronics
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• 제17권5호
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• pp.1203-1210
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• 2017

This paper presents an improved switching selection method for the direct torque control (DTC) of five-phase induction motors (IMs). The proposed method is conducted using optimal switching selection. A five-phase inverter has 32 voltage vectors which are divided into 30 nonzero voltage vectors and two zero voltage vectors. The magnitudes of the voltage vectors consist of large, medium, and small voltage vectors. In addition, these vectors are related to the torque response and torque ripple. When a large voltage vector is selected in a drive system, the torque response time decreases with an increased torque ripple. On the other hand, when a small voltage vector is selected, the torque response time and torque ripple increase. As a result, this paper proposes an optimal voltage vector selection method for improved DTC of a five-phase induction machine depending on the situation. Simulation and experimental results verify the effectiveness of the proposed control algorithm.

• 한국태양에너지학회 논문집
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• 제29권1호
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• pp.1-10
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• 2009

This study was carried out to evaluate the Life Cycle Cost(LCC) of three types of RTPV(Building Integrated Photovoltaic) systems-Glass plus Granite. Crystalline BIPV and See through Amorphous BIPV-which were vertically installed to generate the same power output(76 kW level). Initial investment costs. cost. savings and maintenance costs had been predicted during the period of analysing the LCC of three types of BIPV(Building Integrated Photovoltaic) systems installed for the purpose of evaluating the LCC. In case of cost savings, it had been analyzed by measuring the amount of electric power generated, reduction in lighting load and heat & cooling loads through simulation. From this analysis, it was predicted that the See-through amorphous BIPV offering cost saving advantages demonstrated the economical efficiency similar to the Class plus Granite when it is backed by more than 20 years of durability.

• 멤브레인
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• 제26권4호
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• pp.310-317
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• 2016

리튬이온 이차전지는 리튬이온이 이동하면서 전기화학적 충방전사이클을 완성하는 에너지변환장치를 의미한다. 리튬이온 이차전지는 높은 에너지밀도와 낮은 자가방전률, 상대적으로 긴 수명주기 등 다양한 장점을 갖는다. 최근 전기차 수요증가는 고용량 리튬이온 이차전지 개발을 촉진하고 있으나 음극에서의 dendrite 형성으로 인한 전기적 단락 현상과 전지 폭발 문제와 같은 심각한 안전문제를 야기한다. 또한, 리튬이온 이차전지 구동시 상승된 온도에서 폴리올레핀계열(예 : 폴리에틸렌과 폴리프로필렌) 격리막의 열수축 문제가 발생한다. 이와 같이 낮은 열 안정성은 리튬이온 이차전지의 성능과 수명의 감소로 이어진다. 본 연구에서는 폴리올레핀계열 함침격리막 제조를 위한 중요한 소재로서 술폰화 폴리아릴렌에테르술폰 랜덤 공중합체를 사용하였으며, 제조된 격리막을 이용하여 dendrite 형성과 관련된 금속이온 흡착 능력과 리튬이온전도성, 열적 내구성이 평가되었다.