• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.9
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• pp.721-729
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• 2014

A hybrid desiccant cooling system (HDCS) that uses a heat pump driven by district heating instead of a sensible rotor can provide an increased energy efficiency in summer. In this paper, the summer operation costs and initial costs of both the HDCS and traditional systems are analyzed using annual equal payments, and national benefits are found from using the HDCS instead of traditional systems. In the analysis results, the HDCS reduces the operation cost by 30 compared to the traditional systems, and each HDCS unit has 0.079 TOE per year of primary energy savings and 0.835 $TCO_2$ per year of $CO_2$ emission reduction more than the traditional systems. If HDCSs were to be installed in 680,000 households by 2020, this would produce a replacement power effect of 463 MW. Despite this savings effect, HDCSs require a government subsidy before they can be supplied because the initial cost is higher than that of traditional systems. Thus, this paper calculates suitable subsidies and suggests a supply method for HDCSs considering the national benefits.

• Journal of IKEEE
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• v.23 no.4
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• pp.1280-1287
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• 2019

Grid-connected bidirectional PCS(Power Conditioning System) technology is a technology for implementing distributed renewable energy smart grid. And it is always charged by using power collected from solar modules and commercial grid power among vast smart grid systems, and stored when needed.It is a hybrid energy storage device that allows power to be released into the low voltage system. To this end, a PV input power converter with MPPT function, a bidirectional power converter for battery charging and discharging, and a DC Link input are output to a 3 phase 380V AC system, and if nessary, the bidirectional DC/DC converter We designed and developed a PCS with three power converter structures composed of inverters that perform battery charging. Currently, this system is applied to the site of Jeju, which is vulnerable to power outages and fire accidents.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.2 no.2 s.3
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• pp.65-72
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• 2003

In this work a 6-stage hybrid power amplifier which can be used for the wireless communication systems for MMC(hficrowave Micro Cell) and ITS wireless communication system is designed and fabricated. Ihe power amplifier's each stages was fabricated Hetero-junction Power FET of bare chip type and an alumina substrate with $\varepsilon_{r}$=9.9 and 15-mil thickness. The measured results of power amplifier module showed 33.2$\~$36.5 dB small signal gain, 33.0$\~$34.0 dBm output power at forward frequency (17.6 GHa $\~$ 17.9 CHz) and 36.0$\~$37.0 dB small signal gain, 33.0$\~$34.5 dBm output power at reverse frequency (19.0 GHz $\~$19.2GHz).

• Journal of Aerospace System Engineering
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• v.14 no.5
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• pp.42-48
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• 2020

This research illustrates how the hybrid engine system comprising of a two-cycle reciprocal engine with an integrated generator and a battery is prepared for the design process. The purpose of this research is to increase flight endurance taking advantage of the high energy density of hybrid propulsion systems as well as to cope with current environmental issues by reducing fossil fuel. The hybrid system is designed to offer 6 kW power, and the power can be adjusted by controlling the engine's RPM in accordance with load variations. In addition, the battery is adopted to offer extra electric power that this hybrid system cannot cover, and can function as the main power source in limited time in the case of an emergency situation. Besides that, the generator is directly mounted on an engine crank-shaft, and in turn, they can share the same RPM. Thus, it is hypothesized that this integration method can make a compact design possible by reducing space for the installation in the fuselage of UAVs.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.261-265
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• 2005

This paper describes the DC-DC Converter for Ancillary Power Supply in Hybrid Electric Vehicle. DC-DC Converter is used for charging 12V auxiliary battery supplying electric power to head ramp, audio, ECU etc in automobiles. used DC-DC Converter Topology is PS-ZVS FB(Phase Shifted Zero Voltage Switching Full-Bridge) to reduce switching loss and EMI noise induced by high frequency operating condition. And For easy compensation and stable system response characteristic, current mode control method including slope compensation is employed. Constant current / constant voltage charging control method guarantee stable electric charging of auxiliary battery. Simulation toll PSIM6.0 is used for initial circuit parameter settings and H/W debuging. Thermal problems of Switching components in DC-DC Converter is improved by using Thermo Tracer.

• 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 %.

• 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 KIEE Conference
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• 2015.07a
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• pp.69-70
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• 2015

신재생에너지의무할당제의 도입과 신재생에너지 관련 기술의 급속한 발전으로 인해 자립형 마이크로그리드에 대한 관심과 필요성이 증가하고 있다. 이에 본 논문에서는 기존에 비상용 발전기로 활용되고 있던 수력발전과 유휴 수면을 활용한 수상 태양광발전, 신재생에너지의 출력 안정화를 위한 에너지저장장치의 발전 특성을 분석하고, 차세대 수력발전 기반 하이브리드 전력시스템의 발전원 구성안을 제시하고자 한다.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.259-260
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• 2010

새로운 LLC 직렬 공진 컨버터가 본 논문에서 제안된다. 제안된 컨버트는 1차측에 두 개의 공진 탱크를 가진다. 이 두 개의 공진 탱크로 인하여 컨버터의 입력 전류는 풀 브릿지 LLC 직렬 공진 컨버터에서처럼 연속이고, 하프 브릿지 LLC 직렬 공진 컨버터보다 훨신 낮은 입력 전류 리플을 가진다. 또한, 공진 캐패시터 양단 전압이 하프 브릿지 LLC 직렬 공진 컨버터보다 낮아 낮은 전압 정격을 가진 캐패시터를 사용할 수 있다. 이러한 장점들로 인하여 제안된 컨버터는 fuel cell 시스템과 같이 낮은 source 전류 리플과 넓은 입력/출력 동작 범위가 요구되는 응용에 적합하다. 본 논문에서 제안된 컨버터의 동작 원리를 간단히 설명하고, 380Vdc 입력, 24V/10A 출력 프로토타입 컨버터를 통해 그 동작을 검증한다. 그리고, 제안된 컨버터에서 확장된 두 개의 공진 탱크를 가진 LLC 직렬 공진 컨버터들을 소개한다.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.244-245
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• 2010

Hybrid distribution system is able to use existing AC load under AC power and DC power by providing existing AC power and proper DC voltage at the same time. and, the future expected DC appliance is also available. Hybrid distribution system is divided into two different type. the one is DC common method and the other is AC common method. This paper design each system, and study operating characteristics for improving energy efficiency.