• 전력전자학회논문지
• /
• 제19권6호
• /
• pp.572-581
• /
• 2014

A design and control method of DC/DC converter, which can control variable DC-link voltage to drive a fuel cell electric vehicle (FCEV), is proposed in this study. Given that a fuel cell has low-voltage and high-current characteristics, the required voltage for operating motor must be output through the DC/DC boost converter in the system to drive an FCEV. The proposed converter can choose the output voltage of battery or fuel cell in consideration of the driving mode, as well as control DC-link voltage in accordance with the back electromotive force. The switching lag-time to prevent shortage of pulse-width modulation inverter arms makes distorted current waveform caused by voltage distortion. Through this control method, the proposed converter can reduce the output voltage distortion and current ripple of the inverter, thereby reducing the distorted torque. Simulations and experimental results are presented to verify the reliability of the proposed DC/DC converter.

• 전기전자학회논문지
• /
• 제22권2호
• /
• pp.408-412
• /
• 2018

이 논문에서는 40nm CMOS 공정을 이용하여 제작된 26GHz 가변 이득 증폭기에 대한 연구를 수행하였다. 79GHz를 사용하는 자동차 레이더의 경우 주파수 특성상 회로 전체를 79GHz로 설계 및 매칭 하기 보다는 Down conversion 하여 낮은 주파수대역으로 구동하거나 Up conversion 전에 낮은 주파수 대역을 이용하는 것이 설계 및 구동에 유리하다. 실제적으로 TTD(True Time Delay)를 통해 시간지연을 이용하는 Phased Array System 의 경우에도 현재 기술로는 낮은 주파수로 Down conversion하는 것이 오차를 줄이고 실제적 시간지연을 구현하는데 좋다. 79GHz 주파수의 1/3인 26GHz 주파수 대역에서 동작하는 VGA(Variable Gain Amplifier)에 대하여 설계하였고 1-stage의 cascode amplifier 형태로 구성된 회로에서 VDD : 1V, Bias 0.95V, S11은 < -9.8dB(Mea. High gain mode), S22 <-3.6dB(Mea. High gain mode), Gain : 2.69dB(Mea. High gain mode), P1dB : -15 dBm (Mea. High gain mode) 로 설계되었다. Low gain mode 에서는 S11은 < -3.3dB(Mea. Low gain mode), S22 < -8.6dB(Mea. Low gain mode), Gain : 0dB(Mea. Low gain mode), P1dB : -21 dBm (Mea. Low gain mode)로 설계되었다.

• 한국가스학회지
• /
• 제11권4호
• /
• pp.54-58
• /
• 2007

본 연구에서는 13L급 전자제어식 디젤 엔진을 혼소 엔진으로 개조하여 얻은 결과를 다루고 있다. 혼소 엔진 개조 후 차량의 출력, 연료경제성, 운전성 등을 파악하기 위하여 일정한 경로의 고속도로를 주행하였다. 개조된 차량은 최대 85%의 대체율을 가지며 500 km의 거리를 혼소 모드로 주행하였다. 차량의 주행성능은 디젤 모드의 경우와 거의 동일하였으나, 추월 가속성능이 약간 떨어지는 경향이 있었다. 엔진의 최대출력, 열효율, 배기가스 측정을 위하여 차량 시험과는 별도로 엔진 시험도 동시에 수행하였다. ND-13모드에서 배출가스 배출량 측정 실험을 수행한 결과, 산화촉매를 장착한 혼소모드에서의 배출가스 배출량은 디젤모드에서와 출력은 동일하게 유지하면서 K2006 규제를 만족함을 알 수 있었다.

• 한국대기환경학회지
• /
• 제24권3호
• /
• pp.275-283
• /
• 2008

Since mobile source is a major source of VOCs, quantifying emissions from motor vehicles is an important factor to control VOCs in atmosphere. In this study, in order to evaluate tailpipe VOCs emissions from motor vehicles, mass emissions of non-methane volatile organic compounds from 45 vehicles were determined. Measurements were made on a chassis dynamometer using CVS-75 mode and speed specific drive modes. Target VOCs are 53 compounds determined as the volatile ozone precursors. The individual VOCs composition of vehicle emission and emission rates were also determined. In case of gasoline vehicles, VOCs emission from over 80,000 km vehicles were about 46% larger than less 80,000 km vehicles. The difference in benzene and toluene according to driving mileage was 44% and 26% respectively. The composition of VOCs were different by fuel type. The order of VOCs composition was paraffins>aromatics>olefins in gasoline vehicle emissions, paraffins>olefins>aromatics in light duty diesel vehicle emissions. The VOCs emissions were decreased as vehicle speed increasing. These results will be used to calculate total VOCs emissions from automobiles in the future.

• Journal of Power Electronics
• /
• 제17권2호
• /
• pp.570-578
• /
• 2017

This paper proposes a method to stabilize the output voltage of the secondary side of an Inductive Power Transfer (IPT) system through tuning/detuning via a serial tuned DC Voltage-controlled Variable Capacitor (DVVC). The equivalent capacitance of the DVVC changes with the conduction period of a diode in the DVVC controlled by DC voltage. The output voltage of an IPT system can be made constant when this DVVC is used as a variable resonant capacitor combined with a PI controller generating DC control voltage according to the fluctuations of the output voltage. Since a passive diode instead of an active switch is used in the DVVC, there are no active switch driving problems such as a separate voltage source or gate drivers, which makes the DVVC especially advantageous when used at the secondary side of an IPT system. Moreover, since the equivalent capacitance of the DVVC can be controlled smoothly with a DC voltage and the passive diode generates less EMI than active switches, the DVVC has the potential to be used at much higher frequencies than traditional switch mode capacitors.

• 한국대기환경학회지
• /
• 제22권1호
• /
• pp.127-134
• /
• 2006

In Korea, the number of recreational vehicle (RV) has been increased dramatically recent year. Now there are emission regulations for RV which include pollutants such as CO, HC, NOx, PM. However considering the trend of preferring RV, there needs more strict strategies to control emissions from this type of vehicle. For that reason, we studied emission characteristics of RV and provided basic emission data to evaluate the contribution of RV to the total air pollutant emissions and to establish RV emission management plan. A total of 21 RV were tested on the chassis dynamometer system ranging from small to large engine displacement by vehicle speed, fuel types, regulations and fuel efficiency in order to investigate the characteristics of CO, HC, NOx and PM. For the test modes, 10 different driving speed modes and CVS-75 mode were used. On the basis of this study, RV pollutants emission factors and management strategies will be proposed.

• 대한교통학회:학술대회논문집
• /
• 대한교통학회 1995년도 한-중 국제학술회의 발표논문
• /
• pp.69-76
• /
• 1995

"승차난", "행차난", "정차난"시세계각국재성시화화성시현대화발전 중필연회출현적일개공동적문제,단치리적방법각불진상동. 본문근거상해적실 천,제출료파영향도로교통용량화운행질량적각충인소,종공제교통출행적산생. 개선교통출행적분포, 합리선택출행적방식, 과학선택출행적로선여출행적시간, 대력가강교통관리화도로건설등칠개방면진행통주협조, 종합치리적교통계통관리 기출.병지출타시대도시교통주출곤경적일충투자소, 견효쾌적유효방법.

• 대한교통학회:학술대회논문집
• /
• 대한교통학회 1995년도 한-중 국제학술회의 발표논문
• /
• pp.61-68
• /
• 1995

진쾌파상해건성국제경제, 김융, 무역중심지일, 저시상해성시적발전 목표o실현저개목표,수요유합리적성시총체포국여완선적종합교통체계. 상해시일개구유복잡공능급특정지리조건적특대성시,기발전필연요유 일개괄응뉴합형포국결구적성진체계. 중심성구요안조 "다심개폐식"적 포국결구래조정, 우화토지사용공능. 규화건설호완선적성시종합교통체계,요십분중시항구건설,가강심수 항, 항공항, 신식항적건설;하결심건설호포괄쾌속철로, 고속공로재내적 쾌속교통체계, 완선지함, 지하, 고가상결합적공공교통망락;명학교통정 책여강화규화관리, 사해결교통여합리포국긴밀결합기래.

• 천문학회지
• /
• 제29권spc1호
• /
• pp.389-390
• /
• 1996

The CCDs are widely used in astronomical observations either in direct imaging use or spectroscopic mode. However, the areas of available sensors are too small for large imaging format. One possibility to obtain large detection area is to assemble mosaics of CCD, and drive them simultaneously. Parallel driving of many CCDs together rules out the possibility of individual tuning; however, such optimisation is very important, when the ultimate low light level performance is required, particularly for new, or mixed devices. In this work, a new concept is explored for an entirely novel approach, where the drive waveforms are multiplexed and interleaved. This simultaneously reduces the number of leadout connections and permits individual optimisation efficiently. The digital controller can be designed within a single EPLD (Erasable Programmable Logic Device) chip produced by a CAD software package, where most of the digital controller circuits are integrated. This method can minimise the component. count., and improve the system efficiency greatly, based on earlier works by Han et a1. (1996, 1994). The system software has an open architecture to permit convenient modification by the user, to fit their specific purposes. Some variable system control parameters can be selected by a user with a wider range of choice. The digital controller design concept allows great flexibility of system parameters by the software, specifically for the compatibility to deal with any number of mixed CCDs, and in any format, within the practical limit.

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제11권2호
• /
• pp.111-126
• /
• 2011

The clutch coil mounted on the automotive air conditioner is an important part which actuates the clutch to connect or disconnect the pulley and the compressor according to the climate control condition in an automobile. Here, it is generally required that the clutch coil should ensure the long term durability requirement, such as a warranty for the 10 years of field operation or 160,000 km driving, especially in a brand new item, and so forth. However, some difficulties have arisen in restoring its credibility, since domestic specifications for the part have not been yet unified. In order to ensure the reliability, test methods and assessment criteria should be standardized. Moreover, assessed lifetime under specific conditions and potential failure analysis would be important. In this study, lifetime test specifications for the clutch coil have been reviewed and methodological suggestions are provided to ensure reliability, utilizing a quality function deployment through the potential failure mode effect analysis.