• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.143-151
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• 2018

In this paper, a novel hybrid configuration combining a phase-shift full-bridge (PSFB) and a half-bridge resonant LLC converter is proposed for the On-Board Charger of Electric Vehicles (EVs). In the proposed converter, the PSFB converter shares the lagging-leg switches with half-bridge resonant converter to achieve the wide ZVS range for the switches and to improve the efficiency. The output voltage is modulated by the effective-duty-cycle of the PSFB converter. The proposed converter employs an active reset circuit composed of an active switch and a diode for the transformer which makes it possible to achieve zero circulating current and the soft switching characteristic of the primary switches and rectifier diodes regardless of the load, thereby making the converter highly efficient and eliminating the reverse recovery problem of the diodes. In addition an optimal power sharing strategy is proposed to meet the specification of the charger and to optimize the efficiency of the converter. The operation principle the proposed converter and design considerations for high efficiency are presented. A 6.6 kW prototype converter is fabricated and tested to evaluate its performance at different conditions. The peak efficiency achieved with the proposed converter is 97.7%.

• JSTS:Journal of Semiconductor Technology and Science
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• 제17권2호
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• pp.199-203
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• 2017

Mutually-actuated-nano-electromechanical (MA-NEM) memory switches are proposed for scalability improvement. While conventional NEM memory switches have fixed electrode lines, the proposed MA-NEM memory switches have mutually-actuated cantilever-like electrode lines. Thus, MA-NEM memory switches show smaller deformations of beams in switching. This unique feature of MA-NEM memory switches allows aggressive reduction of the beam length while maintaining nonvolatile property. Also, the scalability of MA-NEM memory switches is confirmed by using finite-element (FE) simulations. MA-NEM memory switches can be promising solutions for reconfigurable logic (RL) circuits.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 전력전자학술대회 논문집
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• pp.387-388
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• 2016

본 논문은 V2G를 위한 Bidirectional OBC를 제안한다. 상용화 시 적시 적용 가능한 높은 역/전송 효율의 Bidirectional OBC 전력회로를 제안하고 베터리 전력을 입력원으로 분산형 전력공급 장치에서 요구하는 품질을 만족하는 전력 생산을 위해 계통연계 회로 및 제어 기술을 제안한다. Bidirectional OBC의 PFC Type은 양방향 구현을 위해 기존 MOSFET과 Diode로 구현된 구조와 달리 모두 IGBT를 이용하여 Single Phase Inverter를 구현 하였으며, IGBT 이용 시 예측되는 Reverse Recovery Loss 개선을 위하여 Hybrid Switch 구조를 제안 하였다. Bidirectional OBC의 DC/DC Type은 전송 및 역송에 따라 Buck동작과 Boost 동작이 가능하도록 설계 하였고 Secondary LC Resonant Topology 가변구조법을 사용 하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.493-495
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• 2008

A new three-level resonant converter suitable for wide input variation is proposed. A hybrid combination of a three-level converter controlled by phase-shift modulation and a half-bridge converter is presented. Since the voltage of each switch is one half of the input voltage, it has advantages of the choice and characteristics of switches. The ZVS operation of the converter is achieved by using the magnetizing current of the transformer. To verify the theoretical analysis, experimental results of the proposed converter are presented.

• Journal of Power Electronics
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• 제9권3호
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• pp.472-480
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• 2009

In this paper, a charge equalization converter with parallel-connected primary windings of transformers is proposed. The proposed work effectively balances the voltage among Lithium-Ion battery cells despite each battery cell has low voltage gap compared with its state of charge (SOC). The principle of the proposed work is that the equalizing energy from all battery strings moves to the lowest voltage battery through the isolated dc/dc converter controlled by the corresponding solid state relay switch. For this research a prototype of four Lithium-Ion battery cells is optimally designed and implemented, and experimental results show that the proposed method has excellent cell balancing performance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.268-270
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• 2000

본 논문은 기계적 스위치와 반도체 스위치를 병렬로 연결한 하이브리드 스위치에 관한 것이다. 제안된 하이브리드 스위치에서 정상상태 동작은 기계적 스위치에 의해 이루어지며 반도체 스위치는 on/off 전환시에만 동작하므로, 반도체 스위치를 위한 냉각 수단이 필요없게 된다. 반도체 스위치에 대한 3가지 제어 방법을 제시하고 시뮬레이션을 통하여 비교하였다. 또한, 5개의 IGBT가 병렬로 연결되고 다시 이것이 20개 직렬 연결된 정격 11kV(RMS)/125A인 반도체 ac 스위치를 설계 제작하였으며, 기본적인 실험 결과가 제시되었다.

• 산업기술연구
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• 제13권
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• pp.89-96
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• 1993

In this paper, an OPS(Optical Protection Socket) unit is designed and prototyped for the application in the optical CPN(Customer Premises Network). The OPS unit, which plays an important role in the CPN for the enhanced network reliability, is consisted of $1{\times}2$ optical fiber splitter, combiner, and $1{\times}1$ optical switch to be a hybrid-typed unit. Various considerations, about power burget and optical information loss have given the most practical design for OPS. From the measurement of the realized OPS unit, it has proved such as the pertinent switching delay time with minimum data loss, the perceptive ability on the ONU degradation, the switching ability on the ONU malfunction.

• BMB Reports
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• 제29권1호
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• pp.88-91
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• 1996

The anaerobically expressed gene aeg-46.5, which had been identified by the operon fusion technique with a hybrid bacteriophage of ${\lambda}$ and Mu, ${\lambda}$placMu53, was studied for its expression pattern and growth. The expression of aeg-46.5 was studied in the wild-type cell and mutant cells that have mutation (s) in the control gene of anaerobic respiration (fnr) and nitrate response (narL and narP). The ${\beta}$-galactosidase reporter gene showed maximum expression in narL host after two hours of aerobic to anaerobic switch in M9-Glc-nitrate medium. Both 40 mM and 100 mM concentrations of nitrate ion in the medium had little effect on expression level. We propose that aeg-46.5 is subject to multiple regulations of anaerobic activation by Fnr, nitrate activation by NarP and repression mediated by NarL.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.797-802
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• 2000

Flow shop scheduling problem involves processing several jobs on common facilities where a setup time Is incurred whenever there is a switch of jobs. Practical aspect of scheduling focuses on finding a near-optimum solution within a feasible time rather than striving for a global optimum. In this paper, a hybrid meta-heuristic method called tabu-genetic algorithm(TGA) is suggested, which combines the genetic algorithm(GA) with tabu list. The experiment shows that the proposed TGA can reach the optimum solution with higher probability than GA or SA(Simulated Annealing) in less time than TS(Tabu Search). It also shows that consideration of setup time becomes more important as the ratio of setup time to processing time increases.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.13-13
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• 2011

Graphene based nano-electronic and nano-electromechanical devices will be introduced in this presentation. The first part of the presentation will be covered by our recent results on the fabrication and physical properties of artificially twisted bilayer graphene. Thanks to the recently developed contact transfer printing method, a single layer graphene sheet is stacked on various substrates/nano-structures in a controlled manner for fabricating e.g. a suspended graphene device, and single-bilayer hybrid junction. The Raman and electrical transport results of the artificially twisted bilayer indicates the decoupling of the two graphene sheets. The graphene based electromechanical devices will be presented in the second part of the presentation. Carbon nanotube based nanorelay and A new concept of non-volatile memory based on the carbon nanotube field effect transistor together with microelectromechanical switch will be briefly introduced at first. Recent progress on the graphene based nano structures of our group will be presented. The array of graphene resonators was fabricated and their mechanical resonance properties are discussed. A novel device structures using carbon nanotube field effect transistor combined with suspended graphene gate will be introduced in the end of this presentation.