• ETRI Journal
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• v.36 no.5
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• pp.829-834
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• 2014

In this paper, a lateral power metal-oxide-semiconductor field-effect transistor with ultra-low specific on-resistance is proposed to be applied to a high-voltage (up to 200 V) integrated chip. The proposed structure has two characteristics. Firstly, a high level of drift doping concentration can be kept because a tilt-implanted p-drift layer assists in the full depletion of the n-drift region. Secondly, charge imbalance is avoided by an extended trench gate, which suppresses the trench corner effect occurring in the n-drift region and helps achieve a high breakdown voltage (BV). Compared to a conventional trench gate, the simulation result shows a 37.5% decrease in $R_{on.sp}$ and a 16% improvement in BV.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.3
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• pp.161-164
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• 2000

A simple methode for calculating the forward voltage drop of IGBTs is presented, on the voltage drops on the p+ body, the reverse biased depletion region between p+body and epi-layer, the epi layer, and the forward biased collector junction. The decrease of the total current density in the epi layer near the p+ body is taken into account. The proposed methode allows a simple but accurate determination of the forward voltage drop in IGBTs, avoiding the complex path taken in the previous model for the forward voltage drops on channel, accumulation region, and epi region. Numerical simulations for 1kV NPT-IGBT with a uniformly doped collector are shown to support the analytical results.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1448-1450
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• 1994

The breakdown voltages of punchthrough-mode diodes with cylindrical junction are analytically calculated, The proposed method, which is based on th Gauss's law, estimates the lateral expansion of the depletion region as well as the electric field and the charge distribution. The proposed method is given in terms of epitaxial layer width, the epitaxial layer doping concentration, and curvature radius of the junction edge. The calculation results agree well with the MEDICI simulation results for various device parameters.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.9
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• pp.1255-1259
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• 2013

A calculation method of the breakdown voltage for the Drain region with the spherical structure in high voltage analog CMOS is proposed. The Drain depletion region is divided into many sub-regions and the doping concentration of each sub-region is assumed to be constant. The field in each sub-region is calculated by the integration of the net charge and the breakdown voltage is calculated using the ionization integral method. The breakdown voltage calculated using the proposed method shows the maximum relative error of 3.3% compared with the result of the 2-dimensional device simulation using BANDIS.

• Advances in Energy Research
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• v.4 no.2
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• pp.163-176
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• 2016

Rapid depletion of fossil based oil, coal and gas reserves and its greater demand day by day necessitates the search for other alternatives. Severe environmental impacts caused by the fossil fire based power plants and the escalating fuel costs are the major challenges faced by the electricity supply industry. Integration of Distributed Generators (DG) especially, wind and solar systems to the grid has been steadily increasing due to the concern of clean environment. This paper focuses on a new simple and fast load flow algorithm named Backward Forward Sweep Algorithm (BFSA) for finding the voltage profile and power losses with the integration of various sizes of DG at different locations. Genetic Algorithm (GA) based BFSA is adopted in finding the optimal location and sizing of DG to attain an improved voltage profile and considerable reduced power loss. Simulation results show that the proposed algorithm is more efficient in finding the optimal location and sizing of DG in 15-bus radial distribution system (RDS).The authenticity of the placement of optimized DG is assured with other DG placement techniques.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.7
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• pp.87-94
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• 2015

Recently, renewable energy sources are under the spotlight. due to the depletion of fossil fuels and environmental problem for the carbon dioxide. Among them, research on the Photovoltaic System using solar energy systems has been actively conducted. In this paper, we propose boosting the insulated DC/DC converter topologies Applied to soft-switching methods used in photovoltaic PCS. The proposed topology is of a type that combines a series of full-bridge converter and a boost converter, a full bridge converter and applying the insulation and soft switching system, the output voltage boost stage is carried out for the boost control. The proposed circuit validity was verified through the PSIM simulation and 5kW PV PCS Prototype and experiments.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.6
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• pp.136-143
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• 1996

A simple analytic model for the planar junctions with multiple foating field limiting rings(FLR) is presented which yields analytic expressions for the breakdown voltage and optimum ring spacings. the normalized potential of each ring is derived as a function of the normalized depletion width and the ring spacing. Based on the assumption that the breakdwon occurs simulataneously at cylindrical junctions of FLR structure where the peak sruface electric fields are equal, the optimum ring spacings are determined. The resutls are in good agreement with the simulations obtained from two dimensional device simulation program MEDICI and with the experimental data reported. The normalized experessions allow a calculation of breakdown voltage and optimum spacing over a broad range of junction depth and background doping levels.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.1
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• pp.17-22
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• 2001

The floating-gate MOSFETs were fabricated by employing 1.5 m n-well CMOS process and their optical-electrical properties were characterized for the application to CMOS image sensor system. Based on the simulation of energy band diagram and operating mechanism of parasitic BJT were proposed as solutions for the increase of photo-current value. In order to realize them, MOSFETs having multi-gate and channel structures were fabricated and 60% increase in photo-current was achieved through enlargement of depletion layer and parallel connection of parasitic BJTs by channel division.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.254-259
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• 2005

The shape of a streamflow hydrograph is very much controlled by the area and depth of snow cover in mountain area. The purpose of this study is to suggest extraction methods for snow cover area and depth using NOAA/AVHRR images in Soyanggang watershed. Snow cover area maps ware derived form channel 1, 3, 4 images of NOAA/AVHRR based on threshold value. In order to extract snow cover depth, snow cover area maps were overlaid daily snow depth data form 7 meteorological observation stations. Snow cover area and depth was mapped for period of Dec. 2002 and Mar. 2003. For evaluating snowmelt changes, depletion curve was created using daily snow cover area in the same period. It is necessary to compare these results with observed data and check the applicability of the suggested method in snowmelt simulation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.4
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• pp.1237-1255
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• 2014

In wireless sensor networks (WSNs), hierarchical clustering is an efficient approach for lower energy consumption and extended network lifetime. In cluster-based multi-hop communications, a cluster head (CH) closer to the sink is loaded heavier than those CHs farther away from the sink. In order to balance the energy consumption among CHs, we development a novel cluster-based routing protocol for corona-structured wireless sensor networks. Based on the relaying traffic of each CH conveys, adequate radius for each corona can be determined through nearly balanced energy depletion analysis, which leads to balanced energy consumption among CHs. Simulation results demonstrate that our clustering approach effectively improves the network lifetime, residual energy and reduces the number of CH rotations in comparison with the MLCRA protocols.