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Dual-Module-Based Maximum Power Point Tracking Control of Photovoltaic Systems
Joung-Hu Park,Jun-Youn Ahn,Bo-Hyung Cho,Gwon-Jong Yu IEEE 2006 IEEE transactions on industrial electronics Vol.53 No.4
<P>The improved maximum power point tracking (MPPT) control method for small-scale dual-module photovoltaic (PV) systems is presented in this paper. With this method, the voltage and current information of each module are shared and utilized for the detection of the maximum-power point (MPP) without measuring power. This approach can be implemented in a simple structure, especially due to the elimination of memory and multiplication devices. The proposed method is verified by a hardware prototype of grid-connected dual-module PV systems with the proposed analog-implemented MPPT controller. In addition, practical issues of the proposed scheme are considered</P>
Joung-Hu Park,Bo-Hyung Cho,Ju-Kwang Lee,Ki-Woong Whang 전력전자학회 2009 JOURNAL OF POWER ELECTRONICS Vol.9 No.2
Recently, 2-dimensional flat light sources have been attracting much attention for its use in LCD backlight applications because of its high luminous efficiency and uniformity. A long-gap discharge, mercury-free flat fluorescent lamp has been developed, which shows a high brightness (>5000 cd/㎡) and high luminous efficacy (60 lm/W). Additionally, it has a wide operating margin and stable driving condition with the aid of an auxiliary electrode. For driving the lamp, a narrow pulse power to maintain the glow discharge state is required. Since there has been no research for this kind of lamp driving, this paper proposes a newly developed short-pulse, high-voltage lamp-driving scheme. The proposed lamp system uses a ballast with a coupled-inductor in order to raise the short pulse voltage up to the lamp ignition level and to obtain energy-recovery action during the glow discharge mode. The operation principles are presented and also the system performances such as the lighting efficiency, spatial and angular uniformities are evaluated by hardware experiments. The results show that the proposed lighting system is a good candidate for the next-generation of LCD backlight systems.
Joung-Hu Park,Bo-Hyung Cho IEEE 2007 IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS PART 1 R Vol.54 No.8
<P>In this paper, a new zero-voltage switching (ZVS) buck converter with a tapped inductor (TI) is proposed. This converter improves the conventional tapped inductor critical conduction mode buck converters that have the ZVS operation range determined by the TI turn ratios. It includes another soft switching range extension method, the current injection method, which gives an additional design freedom for the selection of the turn-ratios and enables the optimal design of the winding ratio of the TI so that the efficiency may be maximized. This soft-switching buck converter is suitable for wide input range step-down applications. The principle of the proposed scheme, analysis of the operation, and design guidelines are included. Experimental results of the 100-W prototype dc-dc converter are given for hardware verification also. Finally, based on the proposed soft-switching technique, a new soft-switching topology family is derived.</P>
Park, Joung-Hu,Cho, Bo-Hyung,Lee, Ju-Kwang,Whang, Ki-Woong The Korean Institute of Power Electronics 2009 JOURNAL OF POWER ELECTRONICS Vol.9 No.2
Recently, 2-dimensional flat light sources have been attracting much attention for its use in LCD backlight applications because of its high luminous efficiency and uniformity. A long-gap discharge, mercury-tree flat fluorescent lamp has been developed, which shows a high brightness ($>5000\;cd/m^2$) and high luminous efficacy (60 lm/W). Additionally, it has a wide operating margin and stable driving condition with the aid of an auxiliary electrode. For driving the lamp, a narrow pulse power to maintain the glow discharge state is required. Since there has been no research for this kind of lamp driving, this paper proposes a newly developed short-pulse, high-voltage lamp-driving scheme. The proposed lamp system uses a ballast with a coupled-inductor in order to raise the short pulse voltage up to the lamp ignition level and to obtain energy-recovery action during the glow discharge mode. The operation principles are presented and also the system performances such as the lighting efficiency, spatial and angular uniformities are evaluated by hardware experiments. The results show that the proposed lighting system is a good candidate for the next-generation of LCD backlight systems.
단일 PWM으로 임의의 개수의 출력제어가 가능한 다출력 전력 변환 회로
박종후(Joung-Hu Park),최규식(Kyusik Choi) 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.4
기존에 사용되고 있는 다중출력 전력변환장치 제어에는 크게 크로스 레귤레이션 방식과 포스트 레귤레이션 방식이 있다. 크로스 레귤레이션의 경우 부품수를 최소화하여 가격 및 사이즈를 절감할 수 있으나, 개별 출력들을 독립적으로 제어하는 정밀한 출력제어는 불가능하다. 포스트 레귤레이션의 경우 정밀한 제어는 가능하나, 여분의 제어스위치를 사용함으로써 효율이 감소하고, 가격이 올라가는 단점이 있다. 본 논문에서는 2개 이상의 다중 출력을, 단일 스위치 혹은 단일 스위치 쌍으로 제어함으로써 이러한 문제점을 해결하고, 궁극적으로 최소의 비용으로 최대의 제어효과를 얻기 위한 단일 PWM 스위칭단을 이용한 다중출력 전력변환회로를 제안하고자 한다. 본 논문에서는 제안된 다중출력 제어 방식의 원리를 설명하고, 다출력 절연형 하프브리지 직류변환기 하드웨어를 제작함으로써 제안된 방식의 가능성올 실험으로 검증하였다.
Hu, Ying,Joung, Joonyoung F.,Jeong, Ji-Eun,Jeong, Yerin,Woo, Han Young,She, Yuanbin,Park, Sungnam,Yoon, Juyoung Elsevier 2019 Sensors and actuators. B Chemical Vol.280 No.-
<P><B>Abstract</B></P> <P>2-(Benzothiazol-2-yl)pyren-1-ol (<B>P3-NS</B>) was developed as a excited-state intramolecular proton transfer (ESIPT)- based sensor for nitroaromatic compounds (NACs). Results of studies of its photophysical and optical properties show that <B>P3-NS</B> exists in various, solvent dependent isomeric forms arising from rotation about the CC bond connecting the benzothiazole and pyren-1-ol rings and the location of the pyrene-OH proton. The results of density functional theory (DFT) calculations enabled identification of the major structures of <B>P3-NS</B> dissolved in different solvents. Upon electronic excitation in nonpolar or weakly polar solvents, <B>P3-NS</B> undergoes an ESIPT reaction to form a product that only weakly fluoresces. In contrast, <B>P3-NS</B> exists in a strongly fluorescent deprotonated form in highly polar solvents. The results of time-dependent DFT calculations indicate that fluorescence quenching of the product generated by ESIPT reaction of <B>P3-NS</B> is caused by intersystem crossing at a conical intersection between S<SUB>1</SUB> and T<SUB>2</SUB> states. The anionic form of <B>P3-NS</B>, present in highly polar solvents, was shown to be a fluorescence sensor for nitroaromatic compounds (NACs). Fluorescence quenching by NACs occurs by protonation of the anionic form of <B>P3-NS</B> (static quenching) and by photoinduced electron transfer from the anionic form to NACs (dynamic quenching).</P> <P><B>Highlights</B></P> <P> <UL> <LI> A new hydroxypyrene derivative <B>P3-NS</B> bearing benzothiazole is developed as a fluorescent sensor for nitroaromatic compounds. </LI> <LI> <B>P3-NS</B> undergoes excited-state intramolecular proton transfer reaction in nonpolar or weakly polar solvents. </LI> <LI> <B>P3-NS</B>, as a sensor, exhibits a selective strong response to picric acid over other nitroaromatic compounds. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>