• Journal of Advanced Marine Engineering and Technology
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• v.35 no.6
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• pp.842-848
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• 2011

A fabricated hybrid control board using multi-communication is designed with a low power 8-bit microcontroller, ATxmega128A1. The microcontroller consists of 8 UART (Universal asynchronous receiver/transmitter) ports, 2 kbytes EEPROM, 128 kbytes flash memory, 8 kbytes SRAM. The 8 URAT ports are used for a multi-communication modem, a GPS module, etc. The EEPROM is used for saving a configuration for running programs, and the flash memory of 128 kbytes is used for storing a F/W (Firm Ware), and the 8 kbytes SRAM is used for stack and for storing memory of global variables while running programs. If we use the multi-communication of CDMA, TRS and RF to remotely control Aid to Navigation, it is able to remove the communication shadow area. Even though there is a shadow area for an individual communication method, we can select an optimal communication method. The compatibility of data has been enhanced as using of same data frame per communication device. For the test, 8640 of data have been collected from each buoy during 30 days in every 5 minutes and the receiving rate of the data has shown more than 85 %.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.11
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• pp.1603-1611
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• 2021

As IMO environmental regulations are tightened, the need to establish a system that can reduce emissions is increasing, and for this purpose, various power control management systems have been studied and implemented as a new energy management system for ships. In this study, we design a control process through modeling for Bi-Directional Converter (BDC) application with bi-directional power flow to link batteries, which are energy storage devices, to conventional generator power systems, and propose mechanisms for batteries optimized for varying loads. This work models MATLAB/Simulink as a BDC and simulates current control and state of charge (SOC) optimization at the time of charging and discharging batteries according to load scenarios. Through this, the battery, power, and load were interlocked so that the generator operated on board could be operated in the optimal operation range, and power control management was performed to enable the generator to operate in the high fuel efficiency range.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1696-1704
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• 2008

The conventional hard disk has been the dominant database storage system for over 25 years. Recently, hybrid systems which incorporate the advantages of flash memory into the conventional hard disks are considered to be the next dominant storage systems. Their features are satisfying the requirements like enhanced data I/O, energy consumption and reduced boot time, and they are sufficient to hybrid storage systems as major database storages. However, we need to improve traditional index management schemes based on B-Tree due to the relatively slow characteristics of hard disk operations, as compared to flashmemory. In order to achieve this goal, we propose a new index management scheme called FNC-Tree. FNC-Tree-based index management enhanced search and update performance by caching data objects in unused free area of flash leaf nodes to reduce slow hard disk I/Os in index access processes. Based on the results of the performance evaluation, we conclude that our scheme outperforms the traditional index management schemes.

• New & Renewable Energy
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• v.9 no.4
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• pp.3-12
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• 2013

This paper proposes the hybrid fuel cell system that can solve disadvantages of existing fuel cell system and ensure high reliability and high stability. The system consists of PEM fuel cell, Ni-MH battery and power management system. In this system, when the power provided from the fuel cell is higher than the load power, the extra energy may be used to charge the Ni-MH battery. When the fuel cell can not provide enough energy to the load, the shortage of energy will be supplied by the Ni-MH battery. Experimental results show that the output voltage is regulated well during load variations. Also, high system efficiency is achieved.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.4
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• pp.409-417
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• 2013

Mu-communication board supported by multi-communication is designed with Atxmega 128A1 which is a low power energy consuming of 8-bit microcontroller. ATxmega128A1 microcontroller consists of 8 UART(Universal asynchronous receiver/transmitter) ports which can be setting appropriate user interface having command line interpreter(CLI) program with each port, 2 kbytes EEPROM, 128 kbytes flash memory, 8 kbytes SRAM. 8 URAT ports are used for the multi communication modem, GPS module, etc. and EEPROM is used for saving a configuration for program running, and flash memory of 128 kbytes is used for storing a Firm Ware, and 8 kbytes SRAM is used for stack, storing memory of global variables while program running. If we uses the hybrid communication of path optimization of VHF, TRS and CDMA to remote control AtoN(aid to navigation), it is able to remove the communication shadow area. Even though there is a shadow area for individual communication method, we can select an optimum communication method. The compatibility of data has been enhanced as using of same data frame per communication devices. For the test, 8640 of data has been collected from the each buoy during 30 days in every 5 minutes and the receiving rate of the data has shown more than 99.4 %.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.6
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• pp.590-596
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• 2020

In the island areas where system connection with the commercial power grid is difficult, it is quite important to find a method to efficiently manage energy produced with independent microgrids. In this paper, a prosumer management system for P2P power transaction was realized through the testing the power meter and the response rate of the collected data for the power produced in the small-scale microgrids in which hybrid models of solar power and wind power were implemented. The power network of the microgrid prosumer was composed of mesh structure and the P2P power transaction was tested through the power meter and DC power transmitter in the off-grid sites which were independently constructed in three places. The measurement values of the power meter showed significant results of voltage (average): 380V + 0.9V, current (average): + 0.01A, power: 1000W (-1W) with an error range within ±1%. Stabilization of the server was also confirmed with the response rate of 0.32 sec. for the main screen, 2.61 sec. for the cumulative power generation, and 0.11 sec for the power transaction through the transmission of 50 data in real time. Therefore, the proposed system was validated as a P2P power transaction system that can be used as an independent network without transmitted by Korea Electric Power Corporation (KEPCO).

• Proceedings of the KIPE Conference
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• 2011.11a
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• pp.299-300
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• 2011

상이한 전기화학적 특성을 가진 단위 셀들을 미리 선별하여 팩의 안전한 운용 및 배터리 관리 시스템의 성능 향상을 위해 스크리닝(screening)은 필수적이다. 그러므로, 본 논문에서는 이산 웨이블릿 변환(DWT;discrete wavelet transform)을 이용한 리튬 이온 배터리 스크리닝 방법을 제안한다. 제안된 방식은 축소된 하이브리드 자동차용 전류프로파일을 통해 얻어진 충방전 전압을 이산 웨이블릿 변환에 적용하여 저주파 전압 성분과 고주파 전압 성분으로 분리하고, 각 단계별로 얻어진 성분들의 통계처리를 실시하여 스크리닝을 구현한다. 특히, 마지막 단계에서의 저주파 전압 성분과 고주파 전압 성분은 배터리의 State-of-health(SOH)를 예측하기 위한 성분으로 정의된다.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.428-430
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• 2008

연료전지차 및 하이브리드차용 전기구동시스템의 냉각성능은 차량의 동력성능을 보장하기 위한 중요한 요소이다. 각 단품의 성능 확보를 위해 냉각수를 허용 온도 이하로 관리해야 하며 이때 라디에이터 방열량과 냉각수 유량이 중요 변수가 된다. 본 논문에서는 현대자동차 연료전지차량의 모터, 인버터를 포함한 100kW 전기구동시스템의 최적 냉각 설계를 위하여 차량주행모드에 따른 전기동력부품의 발열량을 이론적으로 산출하고, 시험을 통하여 냉각시스템의 성능을 검증하였다.

• Proceedings of the KIPE Conference
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• 2008.10a
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• pp.94-96
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• 2008

이차전지는 방전을 통하여 화학에너지를 전기에너지로 변환하여 사용하고 이의 역반응인 충전과정을 통하여 전기에너지를 화학에너지로 변환하여 저장함으로써 반복 사용이 가능하다. 많은 이차전지 중에서 리튬이차전지는 현재 핸드폰, 노트북, PDA 등 휴대용 전자기기가 보편화된 Mobile Energy 시대의 동력원이며, 최근 하이브리드 자동차, 지능형 로봇 등의 신산업분야에 적용하기 위한 고출력, 중/대형 이차전지의 개발이 활발히 진행되고 있다. 아울러 경쟁력을 확보하기 위해 전지부문에서는 에너지 밀도, 출력밀도, 사이클 수명, 안전성 등에서 지속적인 성능향상을 거듭하고 있으며, 활용면에서는 고밀도화에 따른 발열, 발화 사고의 안전성 문제를 해결하기 위해 배터리 보호회로를 필수적으로 장착하며, 이러한 보호회로는 용도에 따라 PCM(Protection Circuit Module), 스마트모듈(Smart Module), BMS(Battery Management System) 등으로 명칭되며, 각 사용분야별로 개발이 활발히 진행되고 있어 전지 시스템의 고안전성 및 고신뢰성을 추구하고 있다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.5
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• pp.709-718
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• 2021

As regulations on environmental pollution of ships have been strengthened, interest in smart ships such as electric propulsion ships equipped with hybrid power systems is increasing. Since batteries used in electric propulsion ships have a larger capacity than batteries used in vehicles, the price is high and maintenance is considered important. The ship's battery is manufactured as an integral type and is managed by the battery management system, and the maintenance and repair of the battery is performed through the replacement of the battery. we design and implement a battery module and a control algorithm using pre-cell for easy battery management. In addition, a controller is designed to transmit the data necessary for the electric propulsion ship power system control to the power control system. When a battery to which the corresponding spare-cell is applied is used, the stability of the ship and the battery system is increased, and it can have an advantage in terms of maintenance and repair.