• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.659-662
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• 1999

As utility pollution take a growing interest, ac/dc converter optimizing utility condition has been vigorously studied in decades. In this paper three phase DCM converter is analyzed and equations for average input currents are presented. Also relationships of voltage gain & duty according to angular velocity are presented and variable frequency controller is implemented using reset integrator which is designed in detail. In result power factor and THD characteristics of 3-stage and 4-stage operation ae compared respectively.

• Progress in Superconductivity and Cryogenics
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• v.4 no.1
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• pp.66-72
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• 2002

This paper describes numerical modeling for thermal characteristic of vapor-cooled current leads under pulse operation. The transient thermal analysis considers the temperature difference between a helium gas (low and a copper lead and temperature dependent properties of helium gas, copper and stainless steel. This numerical modeling was compensated and validated by an experiment with commercially available 100 A vapor-cooled current leads. A proper overloading factor was suggested for the current leads under pulse operation through this modeling, which can significantly reduce heat input to a cryostat.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.10 no.16
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• pp.81-88
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• 1987

This article develops to determine and to allocate the two level factors at the table of orthogonal arrays. The column numbers of two factors and two-factor interaction can be determined in applying the bit-by-bit EX-OR operation. The assignment of the Two factors and Two factor interaction is attained by USING COMPUTER, IBM PC/AT applying algorithm of EX-OR operation Theory.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.224-225
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• 2012

When Power Factor Correction(PFC) boost converter is designed for the universal input range, unwanted burst operation can be found at high line and light load. This operation may cause an audible noise from the boost inductor or sensitive flicker for human eye can be found in case of the display application. In order to solve this difficulty, this paper proposes the new control range compensation method and shows the effectiveness than the conventional method thru the experimental result.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.60-62
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• 2005

The operation and control scheme of reactive power compensator (so called STATCOM) based on voltage source converter is theoretically reviewed. STATCOM for compensation of load power factor is designed and its operation is verified by simulation.

• Journal of Agricultural Extension & Community Development
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• v.15 no.4
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• pp.577-597
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• 2008

The purpose of this study is to examine the effects of residents' perceptions of tourism impact and conflicts on residents' participation in rural tourism village. Method of analysis involves factor analysis and regression analysis in this study. In order to measure the level of perception, three factors(economic benefits, social benefits, social and environmental cost) are derived from the factor analysis. And also in order to measure the level of conflict, two factor(openness of information, leading of operation) are derive from the factor analysis. The result of regression analysis indicate that perceived economic benefits and social benefits are rather greater impacts on residents' participation than social and environmental cost, and also openness of information is rather greater impacts on residents' participation than leading of operation.

• Journal of Power Electronics
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• v.18 no.3
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• pp.879-891
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• 2018

A bidirectional dc-dc converter is used in battery energy storage systems owing to the growing requirements of a charging and discharging mode of battery. The magnetic coupling of output or input inductors in parallel-connected multi modules of a bidirectional dc-dc converter is often utilized to reduce the peak-to-peak ripple size of the inductor current. This study proposes a novel design guideline to achieve minimal ripple size of the inductor current under bidirectional power flow. The newly proposed design guideline of optimized coupling factor is applicable to the buck and boost operation modes of a bidirectional dc-dc converter. Therefore, the coupling factor value of the coupled inductor does not have to be optimized separately for buck and boost operation modes. This new observation is explained using the theoretical model of coupled inductor and confirmed through simulation and experimental test.

• Proceedings of the Safety Management and Science Conference
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• 2013.11a
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• pp.231-241
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• 2013

In recent years, accident induced by human error is increasing in the chemical plant. Human error analysis of the chemical plant was conducted on the basis of past accident. Some company called by A for the basis of a chemical accident. Factor analysis of human errors was separated in plant operation and work. Agency's work of occupational safety & health was classified into four types. It is based on the work before, during work, recovery work, and discontinue work. It was still separated work of human error by analysis and then was derived factor and issue. The human error factor and priority for accident prevention in the chemical plant is presented.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.2
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• pp.217-224
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• 2009

This paper presents a new AC/DC converter scheme for HVDC system to achieve a high power factor operation. The new AC/DC converter consists of two 12-pulse bridge converters in series: the primary and auxiliary converters. Ignition angles of the main and auxiliary converters are controlled independently to maintain the nominal DC voltage and control auxiliary voltage. The resulted DC voltage obtained by superimposing the above two phase modulated voltages can be controlled very rapidly over a wide range, and a high power factor operation is achieved. Performance improvements in power factor and harmonic distortion are validated by theoretic derivations and experiments with prototype HVDC system. With the proposed converters, investment for reactive power compensation and filter in HVDC system can be saved significantly.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.98-100
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• 2003

This paper presents the method for computing the power economic dispatch with an optimal power flow (OPF) computation algorithm, considering the power factor limits constraint. Efficient reactive power planning enhances economic operation as well as system security. Accordingly, an adequate level of power factor limits for the load buses should be evaluated for economic operation. The power factor limits are included and described into the OPF's objective function. The proposed method is applied to IEEE 26 buses system.