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A Study on High Performance Converter Topology for Hydrogen Gas Generation Electrolysis System
Taewon Kang(강태원),Yuran Go(고유란),Yongsug Suh(서용석),Junik Jeong(정준익),Dohawn Rho(노도환) 전력전자학회 2010 전력전자학술대회 논문집 Vol.2010 No.7
This paper investigates a high performance converter topology for hydrogen gas generation electrolysis system. The proposed converter topology consists of full-bridge inverter, medium frequency transformer, and diode rectifier. Hydrogen gas generation electrolysis process considered in the paper is analyzed and characterized by its equivalent circuit. The electrolysis cell is modeled as effective resistance, capacitance, inductance, and internal emf voltage source. The proposed converter topology provides enhanced efficiency of hydrogen gas generation process under the operating condition of dc output voltage with high frequency ripple on it. The high performance operation of proposed converter is confirmed through the simulation with the electrolysis cell considered in the equivalent circuit model.
Taewon Kang,Halim Lee,Jiwon Seo 제어로봇시스템학회 2019 제어로봇시스템학회 국제학술대회 논문집 Vol.2019 No.10
Attempts to organize a new positioning system with signals of opportunity (SOPs) has drawn attention as a substitute for when the global navigation satellite system (GNSS) is unavailable. Among various kinds of SOPs, longterm evolution (LTE) is considered a suitable candidate for a positioning system owing to its high transmission power compared to GNSS signals, high bandwidth, and high data rates. To distinguish LTE signals from each other and to recognize the base transceiver station that transmits each LTE signal, also known as eNodeB, cell identity (cell ID) must be determined. To organize a high-reliability positioning system, the maximum correlation peak value of reference signals and reference signal received quality (RSRQ) can be considered the criteria by which to evaluate the reliability of a determined LTE cell ID. This paper shows the analyzed results of real LTE signals acquired in commercial frequency bands and sampled. The correlation peak value and RSRQ are measured and compared at different spectral and sampling frequencies.
Kang, Taewon,Kim, Hongsik,Lee, Dongwhan THE AMERICAN CHEMICAL SOCIETY 2017 ORGANIC LETTERS Vol.19 No.23
<P>Triazoliptycene fluorophores have been designed and synthesized, in which a three-dimensional propeller-like iptycene motif is employed to suppress intermolecular π–π stacking in the solid state. Key to the success of this modular synthesis is a stereoelectronic bias imposed by the iptycene scaffold, which assists the desired regioselectivity in the C–N cross-coupling step as the last-stage structure diversification from a common precursor.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/orlef7/2017/orlef7.2017.19.issue-23/acs.orglett.7b03239/production/images/medium/ol-2017-03239y_0010.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ol7b03239'>ACS Electronic Supporting Info</A></P>
Taewon Kang,Jaeho Lee,Yongsug Suh 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5
The magnetic coupling of filter inductors is widely utilized in various power electronics application fields, including dc-dc converters in EV charger systems, in order to enhance the filtering performance while maintaining the minimal filter size. The optimal distribution of self and mutual inductance of the coupled inductor is regarded as one of the important design tasks with respect to the coupled inductor. This paper proposes a novel method to design the optimal coupling factor for a generalized n-winding coupled inductor, which generates the least size of inductor current ripple in phase-staggered multi-paralleled dc-dc converters. The explicit mathematical form of the optimal coupling factor for a generalized n-winding coupled inductor in nphase staggered multi-paralleled dc-dc converters is presented. The general equations for the n-winding coupled inductor are verified through the example case of the 3-winding coupled inductor. The experimental results successfully confirmed the newly proposed method of obtaining the optimal coupling factor.
Taewon Kang,Yongsug Suh 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.3
A bidirectional dc–dc converter is used in battery energy storage systems owing to the growing requirements of a charging and discharging mode of battery. The magnetic coupling of output or input inductors in parallel-connected multi modules of a bidirectional dc–dc converter is often utilized to reduce the peak-to-peak ripple size of the inductor current. This study proposes a novel design guideline to achieve minimal ripple size of the inductor current under bidirectional power flow. The newly proposed design guideline of optimized coupling factor is applicable to the buck and boost operation modes of a bidirectional dc–dc converter. Therefore, the coupling factor value of the coupled inductor does not have to be optimized separately for buck and boost operation modes. This new observation is explained using the theoretical model of coupled inductor and confirmed through simulation and experimental test.
Taewon Kang(강태원),Changwoo Kim(김창우),Yongsug Suh(서용석),Hyeoncheol Park(박현철),Byungil Kang(강병익),Daegyun Kim(김대균) 전력전자학회 2011 전력전자학술대회 논문집 Vol.2011 No.7
This paper presents a simple and cost-effective stand-alone rapid battery charging system of 30kW for electric vehicles. The proposed system mainly consists of active front-end rectifier of neutral point clamped 3-level type and non-isolated bi-directional dc-dc converter of multi-phase interleaved half-bridge topology with coupled inductors. The charging system is designed to operate for both lithium-polymer and lithium-ion batteries. The complete charging sequence is made up of three sub-interval operating modes; pre-charging mode, constant-current mode, and constant-voltage mode. The pre-charging mode employs the staircase shaped current profile to accomplish shorter charging time while maintaining the reliable operation of the battery. The proposed system is able to reach the full-charge state within less than 16min for the battery capacity of 8kWh by supplying the charging current of 67A. The optimal discharging algorithm for Vehicle to the Grid (V2G) operation has been adopted to maintain the discharging current of 1C. Owing to the simple and compact power conversion scheme, the proposed solution has superior module-friendly mechanical structure which is absolutely required to realize flexible power expansion capability in a very highcurrent rapid charging system.
Kang, Taewon,Suh, Yongsug The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.3
A bidirectional dc-dc converter is used in battery energy storage systems owing to the growing requirements of a charging and discharging mode of battery. The magnetic coupling of output or input inductors in parallel-connected multi modules of a bidirectional dc-dc converter is often utilized to reduce the peak-to-peak ripple size of the inductor current. This study proposes a novel design guideline to achieve minimal ripple size of the inductor current under bidirectional power flow. The newly proposed design guideline of optimized coupling factor is applicable to the buck and boost operation modes of a bidirectional dc-dc converter. Therefore, the coupling factor value of the coupled inductor does not have to be optimized separately for buck and boost operation modes. This new observation is explained using the theoretical model of coupled inductor and confirmed through simulation and experimental test.