• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.29-29
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• 2005

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.295-296
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• 2013

본 논문에서는 새로운 전류원 공진형 컨버터를 제안한다. 제안한 컨버터는 입력전류 리플이 작으며 모든 스위치와 다이오드의 ZCS 턴온/턴오프를 성취하며 턴온/턴오프 전류의 di/dt가 0이다. 또한, 인터리빙 시 출력전류 리플을 이론적으로 완전히 제거할 수 있다. 제안하는 컨버터의 동작원리를 제시하고 실험을 통하여 타당성을 검증하였다.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.400-400
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• 2004

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.363-363
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• 2004

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.318-320
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• 2007

Single-phase cycloconverters are widely used for ac-ac power conversion especially for speed control of ac drives. In this paper, a new single-phase to single-phase Z-source cycloconverter topology is proposed. The proposed single-phase Z-source cycloconverter can boost to a desired voltage with various frequency. Thus, it is called a frequency step-down and amplitude voltage step-up converter. The operating principle of the proposed topology is presented. Analysis and simulation for this single-phase Z-source cycloconverter are also presented.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.23-24
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• 2015

본 논문에서는 하나의 입력으로 강압과 승압된 두 개의 출력을 가지는 승 강압 겸용 DC-to-DC 컨버터를 제안한다. 승압 출력이 가능한 컨버터는 기존의 부스트 컨버터와 동일한 구조이고, 강압 출력이 가능한 컨버터는 배터리의 직 병렬 가변 결합을 이용한다. 강압출력이 가능한 컨버터 동작에서 배터리는 강압 출력의 입력원이 되어 기존의 벅컨버터보다 2배 이상 강압 가능한 장점이 있다. 본 논문은 제안하는 승 강압 겸용 DC-to-DC 컨버터의 구조 및 동작 모드에 따른 이론적 분석을 시행하고 컴퓨터 시뮬레이션을 통해 타당성을 검증한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.6
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• pp.49-55
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• 2021

Recently, a small tracking radar requires the development of a small millimeter wave tracking radar having a high range resolution that can acquire and track a target in various environments and disable the target system with a single blow. Small millimeter wave tracking radar with high range resolution needs to implement a signal processor that can process wide bandwidth signals in real time and meet the requirements of small tracking radar. In this paper, we designed a signal processor that can perform the role and function of a signal processor for a small millimeter wave tracking radar. The signal processor for the small millimeter wave tracking radar requires the real-time processing of input signal of OOOMHz center frequency and OOOMHz bandwidth from 8 channels. In order to satisfy the requirements of the signal processor, the signal processor was designed by applying the high-performance FPGA (Field Programmable Gate Array) and ADC (Analog-to-digital converter) for pre-processing operations, such as DDC (Digital Down Converter) and FFT (Fast Fourier Transform). Finally, the signal processor of the small millimeter wave tracking radar was verified via performance test.

• Journal of the Korean Society for Railway
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• v.20 no.3
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• pp.329-338
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• 2017

A recent trend of technical development in auxiliary-power-supplies (APS) is to replace 60Hz low frequency transformers with isolated type dc/dc converters. This paper introduces the technical trend in APS structures and proposes a power converter circuit suitable for high-efficient and light-weight APS. By utilizing the resonant converter, which achieves ZCS, to reduce switching losses, various types of APS structures (1-stage and 2-stage) are reviewed, and they are verified by simulation. The full-bridge resonant LLC converter is designed with a 1-stage power converting structure; the resonant converter topology is designed with a 2-stage power converting structure that has a pre-regulator converter to compensate for the wide input voltage range. Both a step-down converter and a step-up converter are designed and compared for the pre-regulator in the 2-stage structure. Operational characteristics are compared with simulation results and loss analyses are presented to proposes appropriate system structure and topologies.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.3
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• pp.323-328
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• 2004

Down-conversion of Eu$^{3+}$ doped LiGdF$_4$ (LGF) for increasing the cell efficiency on dye-sensitized Ti $O_2$ solar cells has been studied. The dye sensitized solar cell (DSC) consisting of mesoporous Ti $O_2$ electrode deposited on transparent substrate, an electrolyte containing I$^{[-10]}$ /I$_3$$^{[-10]}$ redox couple, and Pt counter electrode is a promising alternative to the inorganic solar cell. The structure of DSC is basically a sandwich type, viz., FTO glass/Ru-red dye-absorbed Ti $O_2$/iodine electrolyte/sputtered Pt/FTO glass. The cell without down converter had open circuit potential of approximately 0.66 Volt, the short circuit photocurrent density of 1.632 mA/$\textrm{cm}^2$, and fill factor of about 50 ％ at the excitation wavelength of 550 nm. In addition, 5.6 mW/$\textrm{cm}^2$ incident light intensity beam was used as a light source. From this result, the calculated monochromatic efficiency at the wavelength of 550 nm of this cell was about 9.62 ％. The incident photon to current conversion efficiency (IPCE) of N3 used as a dye in this work is about 80 ％ at around 590 nm and 610 nm, which is the emission spectrum of Eu$^{3+}$ doped LGF, results in efficiency increasing of DSC.C.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.7
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• pp.936-942
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• 2014

As a result of the exhaustion of fossil fuel, interest about renewable energy is increasing day by day. Inter alia, study for wave power energy of which the calculability is high and the available amount is abundant is going along actively. As a float-countweight wave energy converter is equivalent improved structural strength compared with oscillating body type. we made the wave only in order to up and down motion by setting up bulkhead which is called wave camber at the outside of float. This paper mainly focuses on generation amount of plural connected float-counterweight wave energy converter and we calculate the amount. The result, we confirmed that the more a numerical value of nl/L increases, the more amount of electricity rises and also when it is over nl/L=0.40, it is possible to get continuous generation. Through this study, we can use as basic data for design of wave chamber on advantageous condition at the real seas and by way of estimation for generation amount.