• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.1
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• pp.20-28
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• 2003

In this paper, we present results of the comparative analysis of the flicker phenomena in the poly-Si TFT-LCD and a-Si:H TFT-LCD arrays for the development and manufacturing of wide-area and high-quality TFT-LCD displays. We used four different types of TFTs; a-Si:H TFT, excimer laser annealed (ELA) poly-Si TFT, silicide mediated crystallization (SMC) poly-Si TFT, and counter-doped lateral body terminal (LBT), poly-Si TFT. We defined the electrical quantity of the flicker so that we could compare the flickers quantitatively for four different 40" UXGA TFT-LCDs. We identify three factors contributing to the flicker, such as charging time, kickback voltage and leakage current, and analyze how much each of three factors give rise to the flincker in the different TFT-LCD arrays. In addition, we suggest and show that, in the case of the poly-Si TFT-LCD arrays, the low-level (minimum) gate voltages should be carefully chosen to minimize the flicker because of their larger leakage currents compared with a-Si TFT-LCD arrays.

• Journal of Digital Contents Society
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• v.10 no.2
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• pp.209-216
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• 2009

Recently it has shown the tendency that the number of consumers are increasing to see a movie by the live sound and much clear image at the DVD theater instead of video room or general theater. However, current DVD theaters are equipped only with the system which has the function of calculation on charging a fee. In this paper, we suggest more effective DVD cinema management system. It is possible to manage of urgent crisis using the technique of packet switching by this system. In addition, it is possible to manage the sailing goods and new DVD enrollment, assist the effective operation of the manager and make the mutual communication with customers.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.9
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• pp.1260-1268
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• 2012

Recently, lack of power reserve margin was observed quite often. In this paper, we studied the method to secure power source for a short time, to cut the utility power peak load, and to reduce the users electricity bills. Emergency diesel generator of an office building is to be converted into a dual-fuel engine generator which is responsible for a portion of the peak load. Compared to the conventional diesel fuel generator, the proposed dual-fuel engine is able to reduce the generation power cost by dual-fuel combustion, and it also mitigates the building's utility power peak load by charging the building's peak load. If the dead resources (a group of emergency dual-fuel engine generators), as a Virtual Power Plant, are operating in peak time, we can significantly reduce future large power development costs. We investigated the current general purpose electricity bills as well as the records of the building electric power usage, and calculated diesel engine generator renovation costs, generation fuel costs, driving conditions, and savings in electricity bills. The proposed dual-fuel engine generation method reduces 18.1% of utility power peak load, and turned out to be highly attractive investment alternative which shows more than 27% of IRR, 76 million won of NPV, and 20~53 months of payback periods. The results of this study are expected to be useful to developing the policy & strategy of the energy department.

• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.932-939
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• 2012

This paper presents an equivalent circuit model of a LIPB (Li-Ion Polymer battery) for Hybrid Electric Vehicles (HEVs). The proposed equivalent circuit can be used to predict the charging/discharging characteristics in time domain as well as the impedance characteristic analysis in frequency domain. Based on these features, a one-cell model is established as a function of Depth of Discharge (DoD), and a 48-cell model for a battery pack was also established. It was confirmed by experiment that the proposed model predict the discharging and impedance (AC) characteristics quite accurately at different constant current levels. To check the usefulness of the proposed circuit, the model was used to simulate a motor driving circuit with an Insulated Gate Bipolar Transistor (IGBT) inverter and Brushless DC (BLDC) motor, and it is confirmed that the model can calculate the battery voltage fluctuation in time domain at different DoDs.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.4 no.4
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• pp.258-263
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• 2011

In this paper, a high quality battery charge-discharge controller for new & renewal energy power generation system is designed. The proposed new controller has a function to manipulate the battery charging current precisely and it is suitable for various batteries including Lead-Acid battery generally used for solar power generation system. LCD display function is implemented to enhanced the user's convenience and minimization of standby power consumption is realized by optimal design using CAD tools.

• Journal of the Korean Society of Safety
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• v.17 no.4
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• pp.94-100
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• 2002

As the use of automatic handling equipment for sensitive semiconductor devices is rapidly increased, manufacturers of electronic components and equipments need to be more alert to the problem of electrostatic discharges(ESD). In order to analyze damage characteristics of semiconductor device damaged by ESD, this study adopts a new charged-device model(CDM), field-induced charged model(FCDM) simulator that is suitable for rapid, routine testing of semiconductor devices and provides a fast and inexpensive test that faithfully represents ESD hazards in plants. High voltage applied to the device under test is raised by the field of non-contacting electrodes in the FCDM simulator, which avoids premature device stressing and permits a faster test cycle. Discharge current and time are measured and calculated. The characteristics of electrostatic attenuation of domestic semiconductor devices are investigated to evaluate the ESD phenomena in the semiconductors. Also, the field charging mechanism, the device thresholds and failure modes are investigated and analyzed. The damaged devices obtained in the simulator are analyzed and evaluated by SEM. The results obtained in this paper can be used to prevent semiconductor devices form ESD hazards and be a foundation of research area and industry relevant to ESD phenomena.

• Journal of the Korean Society of Safety
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• v.16 no.2
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• pp.57-62
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• 2001

In order to analyze the mechanism of semiconductor device damages by ESD, this paper adopts a new charged-device model(CDM), field-induced charged nudel(FCDM), simulator that is suitable for rapid routine testing of semiconductor devices and provides a fast and inexpensive test that faithfully represents ESD hazards in plants. The high voltage applied to the device under test is raised by the fie]d of non-contacting electrodes in the FCDM simulator. which avoids premature device stressing and permits a faster test cycle. Discharge current md time are measured and calculated The FCDM simulator places the device at a huh voltage without transferring charge to it, by using a non-contacting electrode. The only charge transfer in the FCMD simulator happens during the discharge. This paper examine the field charging mechanism, measure device thresholds, and analyze failure modes. The FCDM simulator provides a Int and inexpensive test that faithfully represents factory ESD hazards. The damaged devices obtained in the simulator are analyzed and evaluated by SEM Also the results in this paper can be used for to prevent semiconductor devices from ESD hazards.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.18-19
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• 2017

This paper shows the design of the high voltage capacitor charger which using a modified series parallel resonant converter. The used silicon carbide Metal-Oxide Semiconductor Field Effect Transistor (SiC MOSFET) is proper for the few hundred kHz of high switching frequency to overcome the bulk resonant inductor and snubber capacitors. Furthermore, to increase the amount of the charging current, three phase delta transformer is used as well as the secondary sides are connected in parallel. In this paper, the design procedure of the high voltage capacitor charger is suggested and the output power is verified by the experimental results with the rated resistor load.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.8
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• pp.1407-1411
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• 2008

In material processing, a laser system with optimal laser parameters has been considered to be significant. Especially, the laser scribing technology is thought to be very important for fabricating DSSC(Dye sensitized solar eel!) modules with good quality. Moreover, the $TEM_{00}$ mode laser beam is the most dominant factor to decide the IPCE(Incident photon to current conversion efficiency) characteristics. In order to get the $TEM_{00}$ mode, a pin-hole is inserted within a simple pulsed Nd:YAG laser resonator. And the spatial field distribution is measured by using three size pin-hole diameters of 2.0, 6.0mm respectively. At that moment, each case has the same laser beam energy by adjusting the discharge voltage and pps(pulse per second). From those results, it is known that the pin-hole size of 2.0mm has the perfect $TEM_{00}$ mode. In addition, at the charging voltage of 1000V, 10pps and the feeding speed of 1.11mm/sec, the SEM photo of FTO(Fluorine-doped tin oxide) thin film layers shows the best scribing trace.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.4
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• pp.100-105
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• 1998

This paper proposes a new control strategy of bidirectional uninterruptible power supply (UPS) with the performance of active power filter which compensates the harmonics and reactive power. With only one power stage, it is working simultaneously as the AC/DC rectifier/battery charger and DC/AC inverter to the operation of battery charging or back-up power supplying. Therefore the operation of the proposed system can be divided into the modes, such as the active power filter mode and the battery back-up power mode. And a novel closed-loop control strategy is used to calculate the reference current. The performance of the proposed 5[kVA] system is verified by the simulation and experimental results.