• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.169-170
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• 2015

본 논문에서는 고효율 에너지 저장 시스템에 적합한 양방향 단일 전력변환 AC-DC 컨버터를 제안한다. 제안하는 컨버터는 단일 전력변환을 통해 저가격, 고효율 특성을 가지며, 기존 양방향 전력변환 시스템에 비해 소형화되었다. 본 논문에서는 양방향 단일 전력변환 AC-DC 컨버터를 능동 클램프를 가지는 플라이백 컨버터로 구현하였다. 전력 용량과 효율을 높이기 위해 연속전류모드를 채택하였으며, 양방향 전류 제어를 위해 분할 적분 제어기를 이용하였다. 최종적으로 시제품을 제작하여 제안하는 양방향 컨버터의 타당성을 검증하였다.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.3
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• pp.248-256
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• 2005

This paper presents the design method of the DC/DC converter using flat transformer which is suitable for midium or large capacity and high density power supply. Flat transformer module is composed and manufactured of multi-transformers in parallel and has a number of parallel single turn secondary windings. Therefore, its leakage inductance is highly decreased and it is more suitable for high frequency operation than conventional one. In this paper, we manufactured and tested 750W AC/DC converter with variable output powers to verify the performance of the flat transformer.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.11
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• pp.46-54
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• 1998

A planar Bi-Sb multijunction thermal converter, which is consisted of a linear or bifilar thin film NiCr-heater and a thin film Bi-Sb thermopile, has been fabricated, and its ac-dc transfer characteristics were examined in a frequency range from 10 Hz to 10 KHz. In order to increase the thermal sensitivity and to decrease the ac-dc transfer error of a thermal converter, the heater and the hot junctions of a thermopile were prepared on a Si$_3$N$_4$/SiO$_2$/Si$_3$N$_4$-diaphragm which acts as a thermal isolation layer, and the cold junctions on the Si$_3$N$_4$/SiO$_2$/Si$_3$N$_4$-thin film supported with the silicon rim which functions as a heat sink. The respective thermal sensitivities in air and in a vacuum of the converter with a built-in bifilar heater were about 14.0 ㎷/㎽ and 54.0 ㎷/㎽, and the ac-dc voltage and the current transfer difference ranges in air were about $\pm$0.60 ppm and $\pm$0.11 ppm, respectively, indicating that the ac-dc transfer accuracy of the converter are much higher than that of a commercial 3-dimensional multijunction thermal converter. However, the output thermoelectric voltage fluctuation of the converter was rather high.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.989_990
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• 2009

최근 신재생에너지원의 사용 및 전기자동차의 이용이 확대되고 있는 실정에서 고승압의 전력변환기의 관심이 높아지고 있다. 이에 본 논문에서는 입출력 절연을 통하여 안전성 향상 및 고승압이 가능하며, 효율이 우수한 Push-Pull 절연형 DC/DC 컨버터를 제안한다. 제안된 컨버터는 출력단에 콘덴서를 이용한 배압 회로를 사용하여 고승압을 실현 하였으며, Soft Switching 방식을 적용하여 고효율화가 가능함을 검증 하였다.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.10
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• pp.713-718
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• 1987

A new method for the modeling of non-ideal dc-dc converters whose switching times are finite is proposed. The effects of finite turn-on, turn-off times, delay time, storage time, reverse recovery process on the system stability, dc transfer function and efficiency are investigated. It is verified how system poles are changed and how dc transfer function and efficiency are decreased by non-ideal switching.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.3
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• pp.357-364
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• 2015

This research presents a DC-DC converter controller implemented with an analog memory. The structure of the converter will contribute to solve the stability problem unavoidable in a conventional closed loop converter. The analog memory will be used for realizing CAM(Contents Addressable Memory) which contains the output of the converter and the relevant duty ratio, respectively. The operation for reading in the memory is executed with an absolute differencing circuit and a WTA(Winner-Take-All) circuit suitable for a nearest-match function of the CAM. We also present a system architecture that enables highly-paralleled fast writing and quick readout as well as high integration density.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.1023-1026
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• 2005

본 논문에서는 SDR(Software Defined Radio) 시스템을 위한 Digital IF(Intermediate Frequency) Up/Down 변환기를 설계하고 성능을 평가하였다. 설계한 시스템은 AD 변환부, DA 변환부 및 Up-Down conversion 기능을 수행하는 FPGA로 구성된다. AD 변환부는 Analog Device 사의 AD6645를 사용하였으며, DA 변환부는 Analog Device 사의 AD9775를 사용하였다. Up-Down conversion 기능을 수행하는 FPGA부는 샘플된 IF 입력을 혼합기와 NCO에 의해 기저대역(DC)으로 다운 시키는 역할을 하며, 14bit의 기저대역(DC) 신호를 혼합기와 NCO에 의해 IF 출력으로 올려주는 역할을 한다. 이러한 설계는 기존의 아날로그 헤테로다인 방식에 비하여 높은 유연성 및 우수한 성능 향상을 보여준다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.11
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• pp.1235-1239
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• 2010

In this work, a wideband technique has been proposed that improves the IF bandwidth of mixers and a 24-GHz down-conversion mixer employing the proposed technique has been designed and fabricated based on 0.13-${\mu}m$ RFCMOS technology. The mixer showed the conversion gain of $2.7{\pm}1.5$ dB from DC to 5.25 GHz IF for a fixed LO frequency of 24 GHz. Measured P-1dB and LO-RF isolation was -8.7 dBm and 21 dB, respectively. The mixer draws DC current of 10.6 mA from 1.3 V supply.

• Proceedings of the KIEE Conference
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• 2007.04c
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• pp.231-233
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• 2007

본 논문은 신 발전방식 중 하나인 용융탄산염형 연료전지(Molten Carbonate Fuel Cell, 이하 MCFC) 발전시스템에서 생성된 전력을 계통에 안정적으로 변환, 주입하기 위한 계통연계형 전력변환기를 설계, 제작하고 성능 시험을 수행한 결과이다. 250kW급 MCFC 시스템의 정격 사양 및 스택의 운전 형태를 기반으로 250kW급 전력변환기 구조 및 단위기기를 설계하였고 전력변환기는 크게 DC/DC 컨버터부와 DC/AC 인버터부로 구성된다. 본 논문은 MCFC 발전 시스템에 적용되는 전력변환기(Power Conditioning System, 이하 PCS)를 제작하고 성능을 확인하는데 목적이 있다.

• Journal of the Korean Society of Radiology
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• v.11 no.3
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• pp.101-108
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• 2017

DC/DC switching power converters are commonly used to generate a regulated DC output voltage with high efficiency. The advanced DC/DC converter uses a PWM-IC with OP-Amp. (Operational Amplifier) to control a MOSFET (metal-oxide semiconductor field effect transistor), which is a switching component, efficiently. In this paper, it is shown that the electrical characteristics of OP-Amp. are affected by radiations of ${\gamma}$ rays using $^{60}Co$ for TID (Total Ionizing Dose) testing and 5 heavy ions for SEL (Single Event Latch-up) testing. TID testing on OP-Amp. is accomplished up to the total dose of 30 krad, and the cross section($cm^2$) versus LET($MeV/mg/cm^2$) in the OP-Amp. operation is evaluated SEL testing after implementation of the controller board.