• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1165-1166
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• 2006

This paper presents performance monitoring results of large scale photovoltaic (PV) system supported by general dissemination & regional energy program in korea government polices for new and renewable energy resources. 80kW PV system and monitoring system is constructed and monitored PV system performance to observe the overall effect of environmental conditions on their operation characteristics. The PV system performance has been evaluated and analyzed for component perspective (PV array and power conditioning unit) and global perspective (system efficiency, capacity factor, and electrical power energy and power quality etc.) for six month monitoring periods.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1563-1566
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• 2002

A 16-bit adiabatic datapath for micro-power RISC processor is designed. The datapath is composed of a 3-read and 1-write multi-port adiabatic register file and an arithmetic and logic unit. A four-phase clock generator is also designed to provide supply clocks fer adiabatic circuits and the driving capability control scheme is proposed. All the clock line charge on the capacitive interconnections is recovered to recycle energy. Adiabatic circuits are designed based on efficient charge recovery logic(ECRL) and are implemented using a 0.35 fm CMOS technology. Functional and energy simulation is carried out to show the feasibility of adiabatic datapath. Simulation results show that the power consumption of the adiabatic datapath including supply clock generator is reduced by a factor of 1.4∼1.5 compared to that of the conventional CMOS.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.215-218
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• 2001

This paper is proposed a sinusoidal input current multi-level ac-dc converter using transformer. The multi-level converter which controls input current by combining Buck converter to Improve input current characteristics. This method, which is multiplying and duplicating output of converter of equal capacity, is able to control unit power factor of input current, reduce the problem caused by high frequency switching, and apply to high power converter because filter is not necessary The feasibility of the circuit is verified by computer simulation using PSIM

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.417-418
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• 2014

본 논문은 PFC (Power Factor Correction)와 절연형 DC-DC 컨버터의 2단 구조를 갖는 가전제품용 저전압 시스템의 효율을 분석하며, 이에 따른 Buck 및 Boost PFC 토폴로지와 절연형 DC-DC 컨버터 효율 및 설계 차이점을 비교한다. PFC 구조에 따른 각 시스템의 역률 규제 만족 여부와 시스템 효율을 이론적 해석 및 시뮬레이션을 통해 검증한다.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.311.2-311.2
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• 2013

Transmutation characteristics of minor actinides in a transmutation reactor based on a Low Aspect Ratio (LAR) tokamak are investigated. One-dimensional neutron transport and burn-up calculation coupled with the tokamak systems analysis were performed to find the optimal system parameters. The dependence of the transmutation characteristics such as neutron multiplication factor, produced power and transmutation rate on an aspect ratio A in the range of 1.5 to 2.0 was investigated. By adding Pu239 in the transmutation blanket as a neutron multiplication material, it was shown that the one unit of the transmutation reactor based on the LAR tokamak producing fusion power of 150 MWth can destroy the minor actinides contained in the spent fuels produced from more than 19 units of l GWe PWRs with production of the power being in the range of 0.9 - 3.4 GWth.

• Journal of Power Electronics
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• v.19 no.1
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• pp.1-10
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• 2019

Current imbalance is the main factor affecting the lifespan of light-emitting diode (LED) lighting systems and is generally solved by active or passive approaches. Given many new lighting applications, independent control is particularly important in achieving different levels of luminance. Existing passive and active approaches have their own limitations in current sharing and independent control, which bring new challenges to the design of LED drivers. In this work, a multichannel resonant converter based on switched-capacitor control (SCC) is proposed for solving this challenge. In the resonant network of the upper and lower half-bridges, SCC is used instead of fixed capacitance. Then, the individual current of the LED array is obtained through regulation of the effective capacitance of the SCC under a fixed switching frequency. In this manner, the complexity of the control unit of the circuit and the precision of the multichannel outputs are further improved. Finally, the superior performance of the proposed LED driver is verified by simulations and a 4-channel experimental prototype with a rated output power of 20 W.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.1
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• pp.66-72
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• 1999

This paper deals with the output characteristics of resonant PWM inverter type X-ray generators connected to different DC power units i.e. a single phase full bridge rectifier, a three phase full bridge rectifier and a power storage unit(PSU). The quality of X-ray beam depends on the pulsating waveforms of DC voltage supplied to the X-ray tube. In a X-ray generator, the waveform of DC output voltage can be affected from affected from harmonic distortion of DC input power. When a tube voltage waveform is distorted, the property of X-ray beam such as reproducibility, linearity and dose can be reduced. Therefore, we compared DC output waveforms and dose with three type of DC power units and show the experimental results in this paper.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.12
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• pp.1647-1656
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• 2013

Although the demand for electricity has been increasing these days, it becomes more difficult to find new sites for large-scale power generation plants near urban areas due to environmental and economic issues. Therefore, new power plants are forced off to rural or desolate coastal areas. As a result, there is significant regional imbalance in power generation and consumption between urban and rural areas in South Korea. This paper investigates the feasibility of high-voltage DC (HVDC) system as a candidate for electric power transmission system from east-coastal sites to metropolitan area. To this end, this paper analyzes transient stability and dynamic impact of a HVDC transmission system and compares the results to conventional high-voltage AC (HVAC) transmission systems via PSS/E simulation. This paper also examines the effect of HVDC system to voltage variation and low-frequency resonance in the neighboring buses in the grid using ESCR(Effective Short Circuit Ratio)과 UIF(Unit Interaction Factor) indices.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.2
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• pp.123-129
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• 2000

This paper desclibes a design method and test results of grid-connected photovoltaic power 당eneration s systems, which consists of solar cells, DCI AC inverter, utility grid. A 50 kW photovoltaic power generation s system including a 3-phase DCI AC inverter is designed and made in order to investigate the system l pelionnance for glid connection. Also the control scheme of a three phase cmrent-controlled PWM inverter W with PI controller is presented by using d-q transformation. The experimental waveforms show that the p proposed system has stable behavior with em unit power factor in utility-interactive operation.

• Journal of Korean Society for Quality Management
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• v.47 no.4
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• pp.895-910
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• 2019

Purpose: The purpose of this study is to lighten the APU (Auxiliary Power Unit) structure of the KAAV (Korea Assault Amphibious Vehicle) through structural analysis. Methods: Commercially-available program (MIDAS.NFX) was used for finite element analysis. Frequency response analysis was performed through linear static and mode analyses to verify the structural stability according to the change of the structural materials. Results: Numerical simulation (linear static, mode and frequency response analyses) results showed that the safety factor of the APU was over 1.5 even under the worst case conditions. The APU made by aluminum structures was expected to be available in the military field, since every requirements in the KDS (Korean Defense Specifications) was fulfilled during the various tests and evaluations. Conclusion: The structural analysis was verified that the structural stability of the APU structure of the KAAV after change of the structural material.