• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.279-285
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• 2007

Since the residential load is an AC load and the output of solar cell is a DC power, the photovoltaic system needs the DC/AC converter to utilize solar cell. In case of driving to interact with utility line, in order to operate at unity power factor, converter must provide the sinusoidal wave current and voltage with same phase of utility line. Since output of solar cell is greatly fluctuated by insolation, it is necessary that the operation of solar cell output in the range of the vicinity of maximum power point. In this paper, DC/AC converter is three phase PWM converter with smoothing reactor. And then, feedforward control used to obtain a superior characteristic for current control and digital PLL circuit used to detect the phase of utility line.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1041-1044
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• 1992

A solar cell should be operated at the maximum output point on the I-V characteristic curve with constant current and constant voltage in order that the solar energy be fully utilized. According to, in this paper, we describes a controller which can track the maximum power point of a solar arry using current and voltage ripple variation of step up chopper system. The control circuit is desinged such that actual current and voltage are sensed directly from the solar cell array. These two signal are then holded sampling and multiplies by a single chip multiplier.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.8
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• pp.42-49
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• 2012

Grid-connected photovoltaic generator system requires high performance PCS(Power Conditioning System) according to the standard of 'Distributed Generation Grid-Connected Technology Standards'. This paper presents the MPPT control method which improves output efficiency through fast tracking to the maximum power point of PV and a reduced self-excited vibration. Secondly, in this paper DVR function was applied to PCS to compensate the voltage sag frequently happening for a power system. The proposed PCS control is analyzed and compared to conventional PCS operating characteristic, the various insolation and loads, and voltage sag condition through PSIM tool. It proves the utility.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.12
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• pp.587-594
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• 2003

This paper presents a design and characteristic analysis of an SRM drive for EPS(Electrically Power Steering) application. A rack mounted EPS system is considered in this paper. A conventional driving room space and mechanical structure are considered in a design stage. In the restricted design conditions, motor parameters are determined for sufficient torque and speed. For the smooth torque generation and simple circuit of power system, 12/8 motor drive is considered. With FEM and magnetic circuit analysis, designed motor is simulated to meet the requirement of specifications. Effectiveness of the suggested SRM drive for EPS application is studied by the drive tests of a prototype motor.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.172-174
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• 2005

Recently, a concern of power qualify increases because of electronic device development and well-being generation. Power quality problems such as voltage sag, harmonics, flicker etc. have adverse effects on electric devices. Therefore, power quality problems have been monitored. This paper studies a detection of voltage sag that is more severer than the others. A voltage sag has been monitored using rms or wavelet method. This paper proposes an advance detection method using wavelet. An error Of Start Point differs error of ending point. We use this difference. So, we respectively revise detection error. Also, we revise multiplying average error rate.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.67-68
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• 2007

The introduction of high brightness LEDs with white light and monochromatic colors have led to a movement towards specialty and general illumination applications. Because drive circuit of illumination LED has an effect on efficiency and life, research about the drive circuit following LED characteristic is needed. This paper proposed a implementation of the stand-alone LED lighting system using battery from photovoltaic power generation.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.152-155
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• 1993

Protective Relay in power system play a prominent part in minimizing power delivery interruptions and help to get a fast and secure restoration when a failure occurs. In order to meet the higher functional requirements in power system, the performance tests on response characteristic of protective relay is essential to ensure reliability. The purpose of this study is as follows: In order to evaluate performance of protective relay, it is intended to develop performance of digital protective relay simulator which is composed of digital protective relay part, behaviour analysis part, waveform generation part and simulation program to simulate pour system in detail.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1696-1698
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• 2005

In this paper, a model that can be used to represent all types of variable speed wind turbines in power system simulations is presented. Wind turbine characteristic equation of a wind turbine is implemented in the RTDS, and the real data of weather conditions are interfaced to the RTDS for the purpose of real time simulation of grid-connection wind power system. The outcomes of the simulation demonstrate the effectiveness of the proposed simulation scheme in this paper. The results show that the cost effective verifying for the efficiency and stability of WPGS.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.10
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• pp.123-130
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• 2016

High-frequency induction heating equipment can heat the metal by applying a High-Frequency power to the resonant circuit. The resonance circuit is composed of the work coil and the conduction-cooled power capacitor, it influences the performance of the heat treatment equipment according to the characteristics of the capacitor. However, dependence on conduction-cooled power capacitor's import is high due to lack of core technology research and development. Minimizing the generation of internal heat transmitted inside during LC resonance, reduce the reactive power loss, there is a need for a capacitor within the voltage characteristic outstanding. To implement localization it is vital that prior study of the analysis on the frequency response characteristic for the finished capacitor advanced manufacturer be implemented. Studying the interpolation method to read the value at any point of the characteristic curve for a given log-log scale was applied to the analysis tool of the capacitor by my proposed algorithm. The simulation for reproducing frequency response curves was attempted by assuming a capacitor in a simplified series equivalent RC circuit to obtain the equivalent series resistance value. It was confirmed that the reproduction rate was the result value above 83% as compared to the simulation of the properties and characteristics on the actual reactive power for Peak value, and that the algorithm can be applicable when analyzing and predicting the characteristic curves of a simpled model capacitor.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.4
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• pp.520-526
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• 2006

Wave Energy is a derivative of the solar energy input to the earth, which is accumulated on open water surfaces by the action of the winds Waves are disturbances in the water surface. This paper is interested primarily in progressive waves, which carry energy from one place to another Waves are irregular in size and frequency. Moreover the surface of the sea is one of the most hostile environments for engineering structures and materials. The idea of harnessing the tremendous power of the ocean's waves is not new. Hundreds of wave energy conversion techniques have been suggested over the last two centuries. Although many WECS (Wave Energy Conversion Systems) have been invented, only a few systems have been tested and evaluated. This paper describes the characteristic of WES (Wave Energy System) in terms of, devices, resource and potential, etc.. Finally, this paper provides a summary of general and specific conclusions and recommendations concerning WECS potential in Korea.