• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.1
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• pp.19-26
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• 2016

In this study, a bidirectional DC-DC converter for idle stop and go (ISG) is developed to reduce fuel consumption. A three-phase non-isolated half-bridge converter is selected through a design method by considering efficiency and volume. According to the state of charge of the batteries at both the low-voltage and high-voltage sides, buck mode, which charges a low-voltage battery from the generated motor energy, and boost mode, which provides power to the motor from the low- and high-voltage battery sides, are required in the ISG system. Hence, an autonomous and seamless bidirectional control method using a variable current limiter is proposed for mode change. A 1.8 kW engineering sample of the proposed converter has been built and tested to verify the validity of the proposed concept. The maximum efficiencies, including gate driver and control circuit losses, are 96.4% in charging mode and 96.1% in discharging mode.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.17-18
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• 2013

본 논문에서는 자동차의 연료 절감을 위한 ISG(Idle Stop & Go) 시스템용 양방향 DC-DC 컨버터를 개발하였다. ISG 시스템 사양에 따라 효율 및 부피를 고려하여 3상 비절연 하프브리지 컨버터를 제안하였으며 또한 프리스케일사의 5643L MCU를 이용하여 디지털 제어기를 개발하였다. 1.8kW급 시작품을 통해 타당성을 검증하였으며 부피는 3.4L, 승 강압시 정격부하효율은 각각 95.1%, 95.5%이며 최고효율은 96.1%, 96.4%를 달성하였다.

• Journal of the Korean Applied Science and Technology
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• v.32 no.2
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• pp.181-187
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• 2015

We found that we could manage the crystal size of active material by controlling the temperature on curing procedure which is one of the process to produce lead acid battery. The active material causes to improve initial efficiency and durability for the batteries. 3BS from the active materials after curing process is better for initial efficiency. 4BS is not good for the initial efficiency but is better than 3BS in durability by 48%. Accroding to our test results of DOD17.5% life test which is for evaluating of automobile applied ISG system, it is not suitable for flooded lead acid battery which is used for the normal automobil but it is proper to AGM lead acid battery.

• Journal of the Korean Applied Science and Technology
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• v.33 no.1
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• pp.83-91
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• 2016

We studied the effect of battery deep cycle according to the way of active materials formation and the creation condition of electrode material, 3BS ($3PbO{\cdot}PbSO_4{\cdot}H_2O$) and 4BS ($4PbO{\cdot}PbSO_4$), in order to develop the batteries for Idle Stop & Go system. During the curing with active materials of anode and cathode, we found that the final creased active material was deformed by temperature control and it effects the durability of batteries. AGM battery and Flooded battery with 3BS active materials have excellent initial performance. And AGM battery with 4BS active materials shows the lower performance relatively. To compare and analyze of the formation efficiency of active materials, we tested the formation chagging steps with 3 steps and 9 steps differently. The results are that AGM battery with 4BS active materials is better on initial performance than AGM battery with 3BS. After the comparison of durability by DOD 17.5% life test, AGM battery is more suitable than flooded battery for the ISG system which needs the frequent deep cycle. In conclusion, AGM battery is the most suitable for ISG system and the life performance shows 80% difference according to the way of formation and curing of AGM batteries.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.407-408
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• 2014

최근 하이브리드 자동차, 지능형 자동차 등을 비롯한 미래형 자동차 분야와 관련된 연구 개발과 맞물려 자동차 전장 회로 시스템은 더욱 복잡해지고 있다. 자동차 전장 시스템의 경향으로 그린카를 들 수 있는데 이에 대한 하나의 방향성은 연비 개선과 최적의 운행조건을 위한 ISG System( Idle Stop & Go system )의 채택으로 가고 있는 추세이다. 여러 장점을 가진 ISG 시스템이지만 시동 모드 시 많은 양의 전류가 순간적으로 흘러가 일순간 전압강하 발생과 높은 스위칭 주파수에 의한 표피효과가 일어난다. 이를 제어하는 기술로 전장회로상의 DC/DC 컨버터 기술이 핵심이라 할 수 있다. 이에 따라 본 논문에서는 확장성이 용이한 고효율 DC/DC 컨버터를 제안하고 모의 실험과 실제 실험을 통해 검토한다.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.125-126
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• 2016

본 논문에서는 자율주행차량의 ISG시스템에서 비상발전용 양방향 DC-DC 컨버터 개발을 위한 최적화 연구 결과를 발표한다. 자율주행차량의 주 전력시스템이 차단되었을 때 차량을 제어하는 시스템에 전력공급이 가능한 비상발전시스템은 현재 개발되지 않은 상태이다. 자율주행차량의 비상발전시스템의 최대 전력은 약 3kW이며 main battery 전압은 48V, sub battery 전압은 12V이다. 본 연구에서는 차량의 연비를 고려한 고전력 밀도와 배터리 수명을 고려한 전류 리플 최소화를 목표로 한다. 이를 위해 차동모드 커플더 인덕터를 가진 4상 인터리브드 방식으로 설계하였고, 최대 98.22%의 효율이 예상된다.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.1
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• pp.71-76
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• 2014

This Research focuses on how to maximize fuel economy improvement of I.S.G. while keeping 12V system. With 12V system the maximum gain of fuel economy with I.S.G. is known to be about 3~5% in FTP-75 mode because engine stop is only conducted in standstill idle. But in this study deceleration engine stop (engine speed is zero) has been tried additionally and the optimum condition for deceleration engine stop was found to maximize fuel economy improvement in practical point of view, the result of which is about 8.8% in FTP-75.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.6
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• pp.1292-1305
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• 2013

Along with the strengthening vehicle environmental regulations and the growing needs for the energy consumption reduction technology, the researches on the engine idle stop system, have been briskly carried out around the automobile manufacturers before the development of alternative energy. Furthermore, there is a movement to disseminate the environment friendly idle stop system by combining the system to the generalized smart key system to not only increase purchasing but also provide the convenience and save the energy as well. In this paper, we designed and implemented the idle stop system algorithm for the aftermarket smart key system with the OBD-II interface. The implemented start stop system is capable of controlling two independent systems, the smart key system and intelligent idle stop system, on a single ECU. In addition, the implemented start stop system standardizes the communication interface with the vehicles to reduce the time required for installing the start stop system to the various vehicles, and satisfies every standard response time limit for the vehicle status request signals.

• Journal of Life Science
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• v.30 no.4
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• pp.402-409
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• 2020

Nervous necrosis virus (NNV) contains a bi-segmented viral genome, RNA1 (3.4 kb, RdRp), and RNA2 (1.4 kb, capsid protein) in a small particle (25 nm). Despite its extremely compact size, NNV has caused serious damage by infecting approximately 120 fish species worldwide since it was first reported in the late 1980s. In order to minimize the damage caused by NNV infection and develop effective vaccines, it is necessary to understand the intra cellular signaling system according to NNV infection. NNV infection induces cell cycle arrest at the G1 phase via the p53-dependent pathway to use the cellular system for its replication. Otherwise, host cells recognize NNV infection through the RIG-1-like receptor (RLR) signaling pathway to control the virus and infected cells, and then ISGs required for antiviral action are activated via the IFN signaling pathway. Moreover, apoptosis of infected cells is triggered by the unfolded protein response (UPR) through ER stress and mitochondria-mediated cell death. Cell signaling studies on the NNV infection mechanisms are still at an early stage and many pathways have yet to be identified. Understanding the various disease-specific cellular signaling systems associated with NNV infection is essential for rapid and accurate diagnosis and vaccine development.