• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1332-1334
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• 2002

Thermoelectric generation is the direct energy conversion method from heat th electric power. The conversion method is a very useful utilization of waste energy because of its possibility using a thermal energy below $150^{\circ}C$ This research objective is th establish the thermoelectric technology on a optimum system design method and efficiency, and cost effective thermoelectric element in order to extract the maximum electric power from a wasted hot water. This paper is considered in manufacturing a thermoelectric generator and measuring of electric resistance of module a thermoelectric modules. It was found that the electric resistance of thermoelectric modules was defined as a temperature functions. The relationship between electric resistance and temperature characteristics can be a analogized as function of electric current.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.59-62
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• 2007

In this paper, we composed solar generation system with multi-phase interleaved boost converter Solar generated voltage is low, so it has need of the boost power conversion device for supply power to normal load. The multi-phase interleaved boost converter is easy to boost voltage and it can be reduced both input current ripple and output voltage ripple because it is composed with multi-phase. We simulated and tested multi-phase interleaved boost converter applied three-phase.

• Journal of IKEEE
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• v.15 no.2
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• pp.129-133
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• 2011

A spread spectrum clock generation is an efficient way to reduce electro-magnetic interference (EMI) radiation in modern mixed signal chip systems. The proposed circuit generates the spread spectrum clock by directly injecting the modulation voltage into the voltage-controlled oscillator (VCO) current source for SATA II. The resulting 33KHz modulation profile has a Hersey-Kiss shape with a rounded peak. The chip has been fabricated using $0.18{\mu}m$ CMOS process and test results show that the proposed circuit achieves 0.509% (5090ppm) down spreading at 1.5GHz and peak power reduction of 10dB. The active chip area is 0.36mm ${\times}$ 0.49mm and the chip consumes 30mW power at 1.5GHz.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.9
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• pp.1351-1358
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• 2017

In this work, we investigated radiation hardness of GaN-based transistors which are strong candidates for next-generation power electronics. Field effect transistors with three types of gate structures including metal Schottky gate, recessed gate, and p-AlGaN layer gate were fabricated on AlGaN/GaN heterostructure on Si substrate. The devices were irradiated with energetic protons and alpha-particles. The irradiated transistors exhibited the reduction of on-current and the shift of threshold voltage which were attributed to displacement damage by incident energetic particles at high fluence. However, FET operation was still maintained and leakage characteristics were not degraded, suggesting that GaN-based FETs possess high potential for radiation-hardened electronics.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.6
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• pp.89-94
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• 2003

Recently many kinds of power transducers have been commercially used to increase the energy efficiency. However, those devices unavoidably produce the harmonics having an integral frequency of fundamental waves. The harmonics should be removed since they have negative effects on the other devices based on fundamental sine waves. As the current information technology makes the PCs more widespread, it is essential to study the harmonics that they produce. In this paper the harmonic generation of a PC has been measured and analyzed. Additionally, the most efficient way of reducing the harmonics has been proposed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.6
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• pp.58-62
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• 2015

When an emergency generator is running, it supplies the power for critical loads. Generator protection requires the consideration of many abnormal conditions that may occur with generators include overvoltages and ground faults. Modern day power systems create harmonics within the electrical network that can have an impact upon the associated protective system. This paper focuses on the analysing of the cause and development of a solution for the malfunction of induction disc type overcurrent ground relay by generation of harmonics during emergency generator operation.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.50-51
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• 2012

The paper presents a non-isolated bidirectional DC-DC converter for use in renewable power generation, battery, electric vehicles (EV) and small scale DC-UPS systems. In the propose design, the conventional interleaved operation of two-inductor boost structure is modified to accommodate bidirectional operation, and zero-voltage-transition (ZVT) is applied, where both the switch and the rectifier diode achieve soft condition without increasing their voltage and current stresses. The proposed converter has the merits of simple circuitry, reduced size, low cost and high efficiency. The operation principle of the converter is analyzed and verified. Also, simulation results of the proposed bidirectional dc-dc converter is shown.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.11
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• pp.1605-1612
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• 2002

Thermodynamic performance analysis has been carried out for a hybrid electric power generation system combining a gas turbine and a solid oxide fuel cell and operating at over-atmospheric pressure. Performance characteristics with respect to main design parameters such as maximum temperature and pressure ratio are examined in detail. Effects of other important design parameters are investigated including fuel cell internal parameters such as fuel utilization factor, steam/carbon ratio and current density, and system parameters such as recuperator efficiency and compressor inlet temperature.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2011.06a
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• pp.79-79
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• 2011

The oceans are an untapped resource, capable of making a major contribution to our future energy needs. In the search for a non polluting renewable energy source, there is a push to find an economical way to harness energy from the ocean. Tidal stream is one of ocean energy form that is being investigated as potential source for power generation. Tidal current turbines are therefore designed as conversion machinery to generate power from tidal currents. A study on energy extraction from tidal currents is presented in this paper.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.5
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• pp.735-740
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• 2008

Recently, the research of PM (Preventive Maintenance) method on the RCM(Reliability-Centered Maintenance) of the system equipment is being actively advanced for a few years. For the most of the current power equipment maintenance, the state of the equipment after maintenance is assumed to be becoming 'as good as new ones' state. However, the state of the power equipment is maintained like the states of the between 'as good as new ones' and 'as bad as old ones' by imperfect maintenance that implies the life decrease of the equipment by frequent breakdown, the error of maintenance process, and so on. So, the Maintenance method considering the real case has to reflect Imperfect maintenance than perfect maintenance. This paper suggests the Preventive Maintenance method by using Quasi - Renewal Theory for the gas turbine equipment as deliberating the imperfect maintenance for the real cases.