• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1326-1327
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• 2008

Recently, the air pollution is supposed is to be the most serious environmental problem. Therefore, a small air cleaner is asked to make comfortable indoor environment for the moderns who have frequent indoor activity. In this study, without generating of the second pollution source, dust in the air and harmful microorganisms can be removed by the electric dust collecting technology which has high reliability and efficiency to be able to remove the impurities even though it is just 0.01${\mu}m$. Accordingly, power sources of the dust collector use, it is not inefficiency and offering to dust collector unstable. In order to overcome the point at issue, a this study, for power factor compensating use the PFC circuit, for removing the noise use EMI filter and for generating the hight voltage use the Cockcroft Walton Circuit. And we study power source on characteristic and improvement.

• Environmental and Resource Economics Review
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• v.11 no.2
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• pp.233-260
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• 2002

This paper tries to analyze the efficiency structure and regulatory effects in electric power industry by using total factor productivity and indices based on cost function method. This paper performed an empirical analysis on the efficiency improvement and optimal scale taking the cost aspect in electricity industry into account. By expanding the cost structure framework, this paper proposes the analytical method regarding the needs of technology regulation and presents the empirical results which can be verified. Hence, this work can play a key role in decision-making of the national power development and regulatory policy. The empirical result indicates that the electricity industry in Korea has been in the state of economies of scale until 1980s, However, due to sustained growth of power generation, economies of scale declined and subsided after 1980s and then diseconomies of scale is shown recent years. The analysis on the effect of technology regulation shows the national large-scale base-load power plant development-oriented policy until so far contributed substantial cost effect to the electricity industry. The empirical result indicates that the reserve requirement as one of means of technology regulation policy did not contribute to the economies of scale but positive effect on the total factor productivity in Korea.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.5
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• pp.845-850
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• 2017

In this thesis, various solutions through four different cases have been sought for an efficiency improvement of the bidirectional LDC for vehicles. For example, it analyzed the reduction factor of the channel resistance and applied the optimum MOSFET applied to the system, and found and improved the efficiency reduction factor of the transformer. As a result, the average efficiency of the developed LDC could be improved from 85% to 94.7%.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.3
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• pp.15-26
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• 2008

This paper proposes a new sinusoidal rectifier which improves input factor and input current waveform without complicated switching modulation such as pulse width or a complicated feed back control. The proposed rectifier consists of a pair of capacitors connected in series, a full bridge diode rectifier, a pair of inductors, and a pair of switching devices connected in series. While the configuration of the sinusoidal rectifier is simple in itself, it effectively reduces the reactive power and harmonics involved(IEC555-2 SC77A90 Class C) in input line current. The excellent properties of the new sinusoidal rectifier are verified by theoretical analysis and experimental results.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1509-1510
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• 2006

ERA PD measuring system has been using for partial discharge evaluation of power appratus in test laboratories. So, the measurement uncertainty of PD measuring system (ERA), such as PD pulse calibrator rise and fall time, sacle factor(k) and linearity, transfer impedance etc, is very important factor of test result in test laboratory. In this paper, we describe tracebility and uncertainty improvement of PD measuring system in test laboratory based on IEC 60270.

• Journal of Power Electronics
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• v.15 no.3
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• pp.621-633
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• 2015

This paper proposes the analysis and design of a DC-side symmetrical zero-current-switching (ZCS) Class-D current-source driven resonant rectifier to improve the low power-factor and high line current harmonic distortion of lighting applications. An analysis of the junction capacitance effect of Class-D ZCS rectifier diodes, which has a significant impact on line current harmonic distortion, is discussed in this paper. The design procedure is based on the principle of the symmetrical Class-D ZCS rectifier, which ensures more accurate results and provides a more systematic and feasible analysis methodology. Improvement in the power quality is achieved by using the output characteristics of the DC-side Class-D ZCS rectifier, which is inserted between the front-end bridge-rectifier and the bulk-filter capacitor. By using this symmetrical topology, the conduction angle of the bridge-rectifier diode current is increased and the low line harmonic distortion and power-factor near unity were naturally achieved. The peak and ripple values of the line current are also reduced, which allows for a reduced filter-inductor volume of the electromagnetic interference (EMI) filter. In addition, low-cost standard-recovery diodes can be employed as a bridge-rectifier. The validity of the theoretical analysis is confirmed by simulation and experimental results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.1
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• pp.34-40
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• 2006

This paper proposed power system for new DC 49[V] telecommunication using forward three-phase PWM rectifier power factor and efficiency for improvement of ripple voltage. Proposed power system for DC 48[V] telecommunication that consists of power conversion devices including switch, inductor and condenser were made between each line, in power inverter device of each switch control turn-on in period of continuity time control to get power factor '1' of sine wave current and on-off of switch lessens peak current that was happened and got conversion efficiency 92.1[%] composing in PWM rectifier of forward form instead of general PWM rectifier. Also, harmonic input regulation value(IEC61000-3-2 Class-As) satisfy input current and reduce ripple factor of output voltage in state that distortion of three-phase supply is overlapped each other.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.6
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• pp.389-396
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• 2018

This study proposes a control method using a repetitive controller for a boost-type PFC rectifier with an APD circuit structure to improve the current distortion caused by DCM condition. Conventional proportional integral controllers have bandwidth limitations in DCM conditions. The performance improvement of the APD controller in the DCM region is verified through simulations and experiments on the compensation of harmonics by the repetitive controller.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2155-2158
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• 1997

This paper describes the performance improvement of dc TIG (Tungsten Inert Gas) welder. The TIG welder consists of single phase full bridge IGBT inverter which incorporates the high frequency transformer, the boost converter for improving the input power factor, and the arc start system. The arc will be generated without fail even when the extension cable between the torch and the power source is 100m long. In addition, the arc start system with a short dc output voltage will generate less EMI noise than the traditional arc start system with a high frequency output voltage. To demonstrate the practical significance of the proposed methods, some simulation studies are presented.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.8
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• pp.15-20
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• 2010

This paper shows a reasonable diversity factor, that was made by the systematic and statistical way considering actual conditions, such as investigated contract power and peak power for the last 5 years of each customer for 20 Lease Apartment. In this paper, it is necessary to analyze the key features and general trend from the investigated data. It made an analysis of the feature parameters, such as average, standard deviation, median, maximum, minimun and thus it was carried out by the linear and nonlinear regression analysis. The standards of demand, diversity, and load density are necessary to create the design of a transformer capacity that is seldom presented in terms for academic study.