• 전력전자학회논문지
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• 제17권3호
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• pp.259-265
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• 2012

This paper introduces a method for design and implementation of a current controller for boost converter operating in continuous conduction mode (CCM) using a digital signal processor (DSP). A Proportional-Integral (PI) type current controller outputs an average voltage command for inductor, used in the input side of the boost converter, and the duty-ratio of PWM (pulse width modulation) signal for switching device is directly calculated from the average voltage command. The gains of the PI current controller are selected such that the current response characteristics are the same as those of a first-order low-pass filter. The proposed current control scheme is implemented using a DSP based on fixed-point math operations and an experimental study has been performed to validate the proposed method.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.890-893
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• 2002

Since 1970s, varistors using metal-oxide resistors have been applied to Gapless surge arresters for power system. In the paper, the structure of metal-oxide surge arresters without gaps for 362kV GIS which is developed the first in korea has been introduced. And the main evaluation items for the metal-oxide resistors which are reference voltage test, residual voltage test, long duration current impulse withstand test and operating duty test is tested and evaluated.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.458-459
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• 2006

System has to be applied as protection at existent supply of electric power system and link is different from when system is operated individually Co-Generation. When equipment is driven Co-Generation that associate in existent equipment in this paper, displayed operating state of function by duty of protective system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 D
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• pp.2260-2262
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• 2004

After steam turbines in power plant drives generator and maintains it at rated speed using high temperature and high pressure steam energy, they regulate the output of generator when synchronized in parallel with the power system. By the way, as the steam flow into turbine can not be reduced fast even though the electrical load is lost, the turbine gets into dangerous situation due to the increase of its speed. At this time, the duty of the turbine governor is "how to limit the speed within its overspeed trip setpoint and escape from danger." For the purpose of it, there are various ways known. Some overspeed protection methods for steam turbines now being operating in korea are introduced in this paper.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 A
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• pp.67-69
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• 1992

This paper presents the new protective device which is developed specifically for use in oil filled distribution transformers. This device is mounted Inside of the transformer and connected between the secondary winding and the secondary bushings. It provides both fault and overload protection to the transformer, and visual warning of the existence of uneconomical loading conditions. It Is available in thermal/magnetic operating device depending upon fault duty required.

• 전기학회논문지
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• 제64권2호
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• pp.260-267
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• 2015

An LCL-type isolated dc-dc converter is analyzed, using ac approximation. Analyses to express characteristics on the proposed converter are derived under steady and ideal elements conditions in this paper. The two operating modes can be identified from the analysis results representing different device conduction sequences. This converter is capable of achieving required output voltage(step up or down) operations with inductance ratio while operated at fixed frequency with constant duty ratio-50%. Experimental results show that the designed converter based on Q has zero voltage switching and constant output voltage at different load variations to verify the analysis.

• 전기전자학회논문지
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• 제2권2호
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• pp.255-262
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• 1998

The neural network can roughly be classified as the specialized control, indirect control and general schemes. Neural network is adopted for MPPT of solar array. And back propagation algorithm also is used to train neural network controller. We investigate the possibilities of $P_{max}$ control using the neural networks, and then we also examine about operating the solar cell at an optimal voltage comprise of temperature compensated voltage with boost converter. Proposed boost converter of MPPT system is studied by simulation and is implemented by using a microprocessor(80c196kc) which controls duty ratio of the boost converter.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.662-667
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• 2000

A simulation procedure for a full transient analysis of the start-up of heavy-duty gas turbines for power generation is constructed. Compressor stages are grouped into three categories (front, mid, rear) and three different stage characteristic curves are applied to consider the different low-speed operating characteristics. Start-up behavior of a typical single-shaft gas turbine for power generation is simulated. The predicted transient behavior shows a good agreement with the field data. Special attention is paid to the effects of the modulation of VIGV on start-up characteristics, which play a key role in the stable operation of gas turbines.

• Journal of Advanced Marine Engineering and Technology
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• 제16권4호
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• pp.60-77
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• 1992

The effects of exhaust gas recirculation(EGR) on the characteristics of exhaust emissions and specific fuel consumption have been investigated using an eight-cylinder, four cycle, direct injection diesel engine operating at several loads and speeds. The experiments in this study are conducted on the fixed fuel injection timing of $38^{\circ}$ BTDC regardless of experimental conditions. In conclusion, it is found that $NO_{x}$ emission is markedly reduced with the drop of burnt gas temperature at high speeds and loads especially as the EGR rate increases, while the soot particulate rises with EGR rate and load at a given engine speed, especially high loads. The reduction of exhaust emissions within the Korea heavy duty diesel engine emission standards can be roughly achieved by the optimal EGR rate without degarding the specific fuel consumption, based on the correlations between exhaust emissions.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1550-1557
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• 2007

New locomotives 8100 & series 8200, based on the BR152 of German railway are suitable for heavy-duty freight traffic as well as for passenger transport. This electric locomotive had applied by trial petition way and 57 car is operating in mainline and industrial line until now. As matter of fact, this has a purpose to help designing and manufacturing the new electric locomotive in these day when almost all the line is changing into the electric fire line. This thesis has a purpose to check whether the actual simulation value properly apply and meet the designing value, comparing the result of the simulation for the performance of developed locomotive with the result of the type test which can be proceed in actual locomotive in korea (evaluating both the design value and the performance of the real locomotive).