• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.4
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• pp.98-104
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• 2014

The technologies employing spray-guided type combustion system for ultra-lean combustion direct injection engine is focused as a promising technology for satisfying emission regulations and improving fuel economy. In the present study, control and design optimization of lean-burn LPG direct injection engine was carried out with control strategy and injection position changes. Inter-injection spark ignition strategy was applied and the effect of the strategy was assessed at relatively higher load operation condition than previous researches. In order to create richer mixture in the vicinity of spark plug electrode, relative distance between the dead-end of injector and the electrode of spark plug was changed.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2002-2004
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• 1998

In this paper, the compensation algorithm of the stator resistance which is essential to improving the performance of the direct vector control system is proposed. This paper focuses on the improvement in the torque response of the direct vector control in a constant speed region. The conventional compensation algorithms are analyzed and a new method is developed to compensate the stator resistance in the direct vector control system. In addition, the effect of the variation of the stator resistance on the drive performance is analyzed for the vector control. The proposed algorithm is very simple to implement that does not require the modifications on the motor model or additional interrupts of the controller. Also, the value of the stator resistance can be obtained in real-time through the measurement of the terminal voltage and current. From the simulation and experimental results, the validity of the proposed scheme is confirmed.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.379-384
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• 2004

A prototype of 750 kW direct-drive wind turbine generator system, KBP-750D is under development in Korea. For the gearless, direct-drive prototype a synchronous generator with permanent magnets has been developed. The upwind 3-blade type machine employs variable speed and pitch control. The operating ranges of wind and rotor speed are 3 to 25 m/s and 9 to 25 rpm, respectively. The tip speed ratio of rotor blade is 7.5, designed for power coefficient 0.47, The blade pitch and torque are controlled with the predefined torque-speed curve according to the conditions of wind and public electric grid. This paper describes the outlines of primary components of KBP-750D.

• Journal of ILASS-Korea
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• v.22 no.1
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• pp.1-7
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• 2017

Recently, Performance and fuel efficiency of gasoline engines have been improved by adopting direct injection (DI) system instead of port fuel injection (PFI) system. However, injecting gasoline fuel directly into the cylinder significantly reduces the time available for mixing and evaporation. Consequently, particulate matters(PM) emissions increase. Moreover, as the emission regulations are getting more stringent, not only the mass but also the total number of PM should be reduced to satisfy the Euro VI regulations. Increasing the fuel injection pressure is one of the methods to meet this challenge. In this study, the effects of increased fuel injection pressures on combustion and emission characteristics were experimentally examined at several part load conditions in a 1.6 liter commercial gasoline direct injection engine. The main combustion durations decreased about $2{\sim}3^{\circ}$ in crank angle base by increasing the fuel injection pressure due to enhanced air-fuel mixing characteristics. The exhaust emissions and number concentration distributions of PM with particle sizes were also compared. Due to enhanced combustion characteristics, THC emissions decreased, whereas NOx emissions increased. Also, the number concentrations of PM, larger than 10 nm, also significantly decreased.

• Journal of the Korea Society for Simulation
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• v.15 no.2
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• pp.51-57
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• 2006

Production environment of semiconductor industry is shifting from 200mm wafer process to 300mm wafer process. In the new era of semiconductor industry, FAB (fabrication) Line Automation is a key issue that semiconductor industry is facing in shifting from 200mm wafer fabrication to 300mm wafer fabrication. In addition, since the semiconductor manufacturing technologies are being widely spread and market competitions are being stiffened, cost-down techniques became basis of growth. Most companies are trying to reduce average cycle time to increase productivity and delivery time. In this paper, we simulated 300mm wafer fabrication semiconductor manufacturing process by laying great emphasis on reduce average cycle time.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.5
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• pp.413-419
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• 2004

In the induction motor direct vector control system using the Gopinath model flux observer, the deterioration of the dynamic response due to the detuned rotor time constant is investigated. To solve this problem, the on line estimation algorithm of the rotor time constant using model reference adaptive control is proposed. The effect of the motor parameter variation on the rotor time constant estimation is analyzed through experiment. The estimation error due to the parameter variation converges within 5%. Thus applying the proposed algorithm to the Gopinath model flux observer, the robust direct vector control system of the induction motor to the parameter variation can be implemented.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.415-415
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• 2007

In this study. it was investigated about optical simulation in direct-type backlight design. Direct-type backlight has been used high-brightness backlight such as LCD television application. The key parameter in designing direct-type backlight was consists of three geometrical dimension such as the distance of two lamps. the gap of lamp and reflection plate and the number of lamps. It has many variation in optical design and it causes the different properties in backlight system. It shows the best values of above parameters; 26mm of the distance of two lamps. 4.5mm of the gap of lamp and reflection plate and 16 lamps. And we produced the specimen as above condition. and acquired good result in backlight such as the value of the brightness is 6436 nit in center of emission area and less than 5% in brightness uniformity. It shows the effective ways of designing backlight system using optical simulation method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1472-1480
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• 2016

When disasters such as earthquake, flood, typhoon, fire and terrorism are occurred a video management system is required which can shoot video on the disaster site, and send it to a server located in the command center that can grasp at a glance the site conditions. In this paper, to know the performance elements information needed to construct the video management system. we presented a method of configuring an ad hoc network based on Wi-Fi direct communication. And we also evaluated the performance through built of environment for the video management system. The evaluated performance test items are 'packet flow tests according to the video compression ratios and the image sizes', 'packet flow tests according to the distance and traffic tests', 'packet flow tests according to whether LOS or not', and 'performance test of scenarios'.

• Economic and Environmental Geology
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• v.34 no.3
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• pp.307-313
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• 2001

Reactive medium including zero-valent metals such as zero-valent iron ($Fe^0$) degrades chlorinated solvents as a contaminant plume flows through the treatment medium. Although the Feo based reactive barrier has been demonstnlted to be a cost effective for trichloroethenc (TCE)-contaminaled plume remediation, current approach is limited by low process eftlciency and uncertain, effective life of the medium. The objective of this study is to develop an enhanced treatment method of TeE-contaminated groundwater using Feo and direct current. The bench-scale test using flow-through $Fe^0$ reactor column confirmed that the application of direct current with $Fe^0$ is highly effective in enhancing the rate of TeE dechlorination. The dechlorination mechanism appears to be reductive, with the electrons supplied by the iron oxidation and external power supply serving as the additional source of electrons.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.4
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• pp.366-376
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• 2002

A sensor fault detection and isolation scheme(SFDIS) is adopted to improve the reliability of direct torque controlled induction motor drives and the experimental results are discussed. Major contributions include: experimental analysis of a few important sensor faults. design and implementation of the proposed SFDIS, and the fault tolerant control system(FTCS). Although the adopted SFDIS employs only one observer for residual generation, the system has the function of fault isolation that only multiple observer schemes can have. To verify the performance of the proposed scheme, the speed control system is designed for the 2.2kW direct torque controlled Induction motor. Hardware of the control system consists of a control board using TMS320OVC33 and a power stack using IPM. Experimental results for various type of sensor faults show the effectiveness of the SFDIS and the FTCS.