• KIPE Magazine
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• v.10 no.1
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• pp.18-21
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• 2005

• ICROS
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• v.2 no.3
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• pp.71-80
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• 1996

이 글에서는 원자력발전소내의 작업을 위한 로봇연구의 동향과 서울대학교 로보틱스 및 지능시스템 연구실에서 한국전력 전력연구원과 공동으로 개발하고 있는 원전 이동감시 및 방사선 측정용 원격조종 로봇의 개발사례를 소개하고자 한다.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.145-149
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• 2000

A single-stage power factor correction AC/DC converter with a simple link voltage suppressing circuit (LVSC) for the universal line application is proposed. Using this simple circuit a low link voltage can be realized without deadbands at line zero-crossings. The proposed converter is analyzed and a prototype converter with 5C, 12V output is implemented to verify the performance. The experimental results show that the link voltage stress and efficiency are about 447V and 81%, respectively.

• Journal of the Korean GEO-environmental Society
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• v.8 no.6
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• pp.13-19
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• 2007

This study examines a cause for damage of synthetic resins straight pipe occurred after pipe construction of underground electric power duct pipelines of ${\bigcirc}$ section work, ${\bigcirc}$ line, ${\bigcirc}{\bigcirc}$ city railroad. For this, we analyzed a parameter used for plan and structural analysis through a literature review. And the site condition was analyzed in detail, and test construction of the pipe line that simulated the site pipe line and test on compaction by watering were performed. In addition, an examination on subsurface settlement influence of foundation ground through a structural safety and a numerical analysis of power transmission pipe line was performed. As a result of the performance, relative density gained by compaction by watering was more than average and relative degree of compaction according to technical specification standard showed the result of about 90% in the case of good compaction by watering.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.191-192
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• 2012

옥외 LED 조명은 수 많은 응용 분야가 있고, 출력 전력 크기에 따라 전력단이 single-stage 와 two-stage 구조로 나뉜다. Single-stage 구조는 낮은 전력 LED 조명에 적합하지만, 60~70W 이상에서는 효율이 떨어지고 변압기의 크기가 커져서 적용하기가 힘들다. 반면에 two-stage 구조는 보통 큰 전력이 필요한 응용분야에 사용되지만, 낮은 부하에서 낮은 역율을 나타내므로 넓은 출력전력 범위를 갖는 분야에 사용되기 어렵다. 이 문제를 해결하기 위하여 본 논문은 pulse duty cycle, pulse frequency modulation 제어 방법을 갖는 interleaved single-stage flyback AC-DC converter 를 제안한다. 제안된 컨버터는 입력 전압이 낮고 부하가 큰 경우 높은 효율을 보이고, 입력 전압이 높고 부하가 아주 작은 경우에도 높은 역율과 낮은 전류 왜곡을 보인다. 그 결과 하나의 AC-DC 컨버터를 넓은 출력전력 범위를 갖는 LED 조명분야 적용시킬 수 있다. 제안된 컨버터의 타당성을 검증하기 위하여 81W prototype을 가지고 실험하였다.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.352-357
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• 2003

A new single stage power factor correction(PFC) AC/DC converter based on zero voltage switching(ZVS) full bridge topology is proposed. Since the series-connected two transformers act as both output inductor and main transformer by turns, the proposed converter has a wide ZVS range without additional devices for ZVS. Furthermore, since there is no need to use an output inductor, the proposed converter features high power density. The proposed converter gives the good power factor correction and low line current harmonics distortion. A mode analysis and experiment results are presented to verify the validity of the proposed converter.

• Proceedings of the KIPE Conference
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• 2001.12a
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• pp.119-123
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• 2001

In this paper, a DCM operated boost integrated single-stage forward-flyback converter is proposed. This proposed converter has high power factor, low harmonic distortion, and tight output regulation. To increase efficiency, zero voltage switching with asymmetrical control is used. This converter also give low voltage stress in switch and this results in low conduction loss with low turn-on resistance.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.639-642
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• 1999

An integrated zero current switching(ZCS) quasi-resonant converter(QRC) for power factor correction and high efficiency with single switch is proposed in this thesis. Boost integrated circuit operating discontinuous conduction mode(DCM) and QRC are used for power factor correction and reducing switching loss, respectively. A prototype converter has been designed and experimented. At rated condition, the THD in the input current waveform of this prototype has approximately 18%. The efficiency is obtained about 70%, the power factor is about 0.985 as well. Therefore, the proposed converter is suitable for a low power level converter with operating switching frequency above several hundred KHz.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.43-45
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• 2006

대부분의 컨버터들은 초기 기동시에 MOSFET 전류와 전압의 과도한 상승을 막아주기 위해서 Soft Start 기능을 갖고 있다. 하지만 제어기 내부의 지연시간이나 LEB(Leading Edge Blanking) 시간 등으로 인해 MOSFET은 무시할 수 없는 상당한 기간의 최소 턴온 시간(Minimum Turn-on Time)을 갖게 되고, 이로 인해 드레인 전류가 과도하게 상승하는 현상을 보이게 된다. 본 논문에서는 이런 현상이 발생할 수 있는 초기 기동이나 출력단 단락시에 과도한 드레인 전류의 상승을 막아주는 방법을 제시하고자 한다.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.254-256
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• 2006

A Novel way to support typical Thermal Shut Down(TSD) circuit is proposed. In power ICs, on-time or on-duration is the key factor to anticipate an abrupt increase of internal temperature. Such an abrupt raise of the temperature can cause TSD circuit cannot protect on proper time due to the temperature detection delay come from the physical distance or the imperfect coupling between heat sources and detector. The proposed circuit checks the duty ratio touched their maximum or not in every cycle. Once duty ratio touches the maximum duty, new circuit generates the warning signal to the TSD circuit and lowers pre-determined temperature for shut down to compensate the detection delay. The novel circuit will be analyzed to the transistor level and checked the validity by simulation.