• 대한화학회지
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• 제21권4호
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• pp.246-255
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• 1977

여러 종류의 層間 陽이온을 가지고 있는 層狀 硅酸鹽上에서 일어난 methylmethacrylate의 吸着에 關하여 赤外線 分光法과 X-ray로 硏究하였다. 吸着된 methylmethacrylate의 여러 개의 特性 carbonyl band가 陽이온의 種과 脫水溫度에 따라서 다르게 1723∼1547$cm^{-1}$의 範圍에서 나타났다. 190$cm^{-1}$程度로 shift한 carbonyl 伸縮 band는 polyvalent 陽이온에만 나타났으며 $>C=O{\cdot}{\cdot}{\cdot}M^{n+}$型 着物形成 基因하는 것이었다. 1703∼1640$cm^{-1}$에서 나타난 band는 carbonyl 酸素와 陽이온 水 또는 陽이온 水酸基와의 水素結合에 依한 것이었고 shift한 정도는 層間 陽이온의 polarizing power와 좋은 相互 關係를 이루었다. 그러나 1723$cm^{-1}$에서 나타난 band는 陽이온의 鍾과는 相互 關係가 없었으며 carbonyl ,酸素와 表面 水酸基와의 相互 作用으로 因한 것이었다. Interlamellar spacing을 계산해 본 結果 methylmethacrylate의 分子平面은 硅酸鹽의 層과 平行하게 놓여 있는 것 같다.

• 조명전기설비학회논문지
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• 제14권5호
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• pp.27-35
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• 2000

본 논문에서는 공진형 Full Bridge DC-DC 컨버터의 고효율 및 고밀도의 적류 안정화 전원장치의 전력제어를 위해서 스위칭 소자 대한 스위칭 손실 스위칭 스트레스를 줄이고, 가변입력에 대한 정상상태의 오차를 없애기 위해서 개선된 소프트 스위칭 방법인 디지털 I-PD 워상천이 제어기를 설계하여 적용하고자 한다. 공진형 FB DC-DC 컨버터에 대한 회로분석을 통한 모드별 소프트 스위칭 동작 특성을 해석하고, 질렬공진 등가회로로부터 이산시간계 상태방정식을 도출하며 입력에 대한 급변하는 error를 막고, 정성상태 오차없이 추종하도록 하는 디지털 I-PD형 제어기를 구성한다. 또한 고속의 소프트 스위청 공진혐 FB DC-DC 컨버터 제어기에 위해서 디지털 I-PD제어기에 위상천이 제어기를 부가하므로서 컨버터의 중량을 줄이고 스위치 소자의 스트레스가 경감되는 컨버터를 실현하였다.

• 조명전기설비학회논문지
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• 제17권1호
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• pp.94-102
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• 2003

본 논문은 고주파 전원에 사용되는 풀 브릿지 부하 병렬형 고주파 공진 인버터 회로를 연구대상으로 하고 출력제어기법으로는 펄스 주파수 변조(PFM, 펄스 폭 변조(PWM) 그리고 펄스 위상 변화(Phase-Shift)잎 경우를 비교 검토하였다. 회로의 해석은 정규화 파라메타를 도입하여 범용성 있게 기술하였고, 인버터 특성은 3가지 구동신호패턴에 의한 스위칭 주파수($\mu$), 펄스폭($\theta$d), Phase-Shift의 위상차각($\phi$)의 변화와 제 파라메타에 따라 특성 평가를 행하였다. 실험을 통해 이론해석의 타당성을 검증하였다. 향후, 3가지의 구동신호제어기법에 의한 특성들은 유도가열 응용, DC-DC 컨버터 등의 전원 시스템의 출력제어 시에 유용한 자료로 제공될 것으로 사료된다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 춘계학술대회
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• pp.181-184
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• 2005

Operating conditions of photovoltaic power generator is very sensitive to the PV modules. The PV module's control is an importance issue in the removing DC ripple noise. In this paper, the phase-shifted-carrier technique, which is a new three-step dc-dc power multi-converter schemes, is applied to solar generator system to improve the output current waveform. The novel type of three-step dc-dc converter presented has many features such as the good output waveform, high efficiency, low switching losses, low acoustic noise. The circuit configuration is constructed by the conventional full-bridge type converter circuit using the isolated DC power supply for which the solar cell is very suitable. In the end, a circuit design for understanding three-step dc-dc converter and new solar power system were presented

• JSTS:Journal of Semiconductor Technology and Science
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• 제17권1호
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• pp.120-128
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• 2017

This paper describes a neural stimulation system that employs an inductive coupling link to transfer power and data wirelessly. For the reliable data and power delivery, a self-referenced amplitude-shift keying (ASK) demodulator and a wide-range voltage regulator are suggested and implemented in the proposed stimulator system. The prototype fabricated in 0.35 um BCD process successfully transferred 1.2 Kbps data bi-directionally while supplying 4.5 mW power to internal MCU and stimulation block.

• JSTS:Journal of Semiconductor Technology and Science
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• 제6권4호
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• pp.275-280
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• 2006

We propose Doherty power amplifier structure which can be integrated in Silicon RF ICs. Doherty power amplifiers are widely used in RF transmitters, because of their high Power Added Efficiency (PAE) and good linearity. In this paper, it is proposed that a method to replace the quarter wavelength coupler with IQ up-conversion mixers to achieve 90 degree phase shift, which allows on-chip Doherty amplifier. This idea is implemented and manufactured in CMOS 5 GHz band direct-conversion RF transmitter. We measured a 3dB improvement output RF power and linearity.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.591-594
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• 2005

Islanding of PV systems occurs when the uitilty grid is removed but local sources continue to operate and provide power to local loads. Islanding Is one of the serious problems in an electric power system connected with dispersed power sources. Also, this scan present safety hazards and the possibility of damage to other electric equipments. If the real and reactive power of RLC load and PV system are closely matched, islanding phenomena can't be detected by the passive methods. Several active methods were proposed to detect islanding phenomena. The most effective method is SFS method which was suggested by Sandia National Laboratory. In this paper, a new anti-islanding algorithm is proposed and its validity is verified through simulation and experimental results for utility interconnection of PV system.

• Journal of Power Electronics
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• 제16권3호
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• pp.1141-1151
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• 2016

This study proposes a novel islanding detection method for distributed photovoltaic (PV) systems with multi-inverters based on a combination of the power line carrier communication and Sandia frequency shift islanding detection methods. A parameter design method is provided for the novel scheme. On the basis of the designed parameters, the effect of frequency measurement errors and grid line impedance on the islanding detection performance of PV systems is analyzed. Experimental results show that the theoretical analysis is correct and that the novel method with the designed parameters has little effect on the power quality of the inverter output current. Non-detection zones are not observed, and a high degree of reliability is achieved. Moreover, the proposed islanding detection method is suitable for distributed PV systems with multi-inverters.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 춘계학술대회 논문집 에너지변화시스템부문
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• pp.152-155
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• 2009

In high power application, PFC(Power Factor Correction) pre-regulators are generally required. PFC pre-regulators could achieve unity power factor, reduce line input current harmonics and utilize full line power. Interleaving PFC converters could reduce input ripple current, output capacitor ripple current and inductor size. With this closed loop interleaving method, both two phase converters are working at the boundary between continuous and discontinuous mode and accurate 180 degree phase shift is achieved. Implementation of this strategy could be easily integrated to the control chip. Finally, experimental results of a two-phase interleaved boost PFC are presented to verify the discussed features.

• 전기전자학회논문지
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• 제23권1호
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• pp.314-317
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• 2019

Recently, the symmetric superposition coding (SSC) [3] is proposed for a solution for the error propagation (EP) due to the non-perfect successive interference cancelation (SIC) in non-orthogonal multiple access (NOMA). We analyze the performance of NOMA with the SSC. It is shown that the performance of the SSC NOMA is the same as that of NOMA with the normal superposition coding (NSC) for the power allocation factor less than 20%, the SSC NOMA performance is better than the NSC NOMA performance up to the power allocation factor 80%, and the SSC NOMA performs worse than the NSC NOMA for the power allocation factor greater than 80%. As a result, the SSC should be used with consideration of the power allocation.