• New & Renewable Energy
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• v.2 no.2 s.6
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• pp.16-22
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• 2006

This paper present the performance evaluation of PV systems installed at Tibet area of China in order to identity the key factors that determines system operation at a severe climate conditions and promote the cooperation of PV technology between Korea and China. The installed systems consist of 100kW on-grid connected PV systems, BOS(balance of systems), data acquisition and transmission equipments. The Korea side supplied the solar cell, BOS like as inverter, control box and monitoring system. And the Chinese side assembled solar module, constructed site and built control house. It has been shown that the average radiation per monthly from Tibet is 1.5 times larger than that from Mokpo. Also, radiation time from Tibet is 2hour higher than that from Korea.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.125-129
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• 2006

This paper presents the isolation and performance evaluation of PV systems installed at Tibet area of China in order to identity the key factors that determines system operation at a severe climate conditions and promote the cooperation of PV technology between Korea and China. The installed systems consist of 100kW on-grid connected PV systems, BOS(balance of systems), data acquisition and transmission equipments. The Korea side supplied the solar cell, BOS like as inverter, control box and monitoring system. And the Chinese side assembled solar module by using Koreans solar cells, constructed site and built control house.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.244-244
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• 2007

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.6
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• pp.469-475
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• 2008

In this paper, control of small PEM(Proton Exchange Membrane) fuel cell stack by a microprocessor is introduced. The water management of fuel cell stack inside, a key technique in fuel cell control, can be achieved by adjusting the required air flow for fuel and cooling, and by purging the excessive water from the stack. It is very important to precisely control the BOS(Balance of Stack) since the stable operation of the fuel cell system mainly depends on it. In this study the fuel efficiency of the system is improved by the control of the system based on the measured air flow and purge cycle during the optimal operation and its effectiveness is proved by the experiments. The operating stability of the system is improved by the developed controller using a microprocessor and it is expected to be widely used for the control of small PEM fuel cell stack.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.284-287
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• 2007

This paper presents the performance evaluation of PV systems installed at Tibet area of China in order to identity the key factors that determines system operation at a severe climate conditions and promote the cooperation of PV technology between Korea and China. The installed systems consist of 100kW on-grid connected PV systems, BOS(balance of systems), data acquisition and transmission equipments. The Korea side supplied the solar cell, BOS like as inverter, control box and monitoring system. And the Chinese side assembled solar module, constructed site and built control house. It has been shown that the average radiation per monthly from Tibet is 1.5 times larger than that from Mokpo. Also, radiation time from Tibet is 2hour higher than that from Korea. The economical analysis has shown that with the current prices, investment in a grid connected PV systems is generally profitable

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.65.2-65.2
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• 2010

Currently the variety of governmental business support and research for supplying solar energy have been actively progressed. As of now, however, There are no practical testing infrastructures of grid-connected photovoltaic system which test performance of solar power facility in domestic. Therefore, in KEPRI, there is in progress construction of practical testing ground of 500 kW class grid-connected PV System for developing the evaluation of the performance technology including the Module, PCS, and etc, that is the important instrument of the PV System, in Gochang area. It analyzed the site creation work for constructing the practical testing ground and new construction of control room and the unit standards, specifications and capacity of required equipment. For the system detailed design, configuration, instrument-specific parameters established, power generation predictions of Array Type and the components of testing ground are needed to build.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.9
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• pp.823-826
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• 2010

In this study, the control method of assistive robot was developed for the elderly. The control method of gait-assistant-robot was proposed considering the change of COP (Center of Pelves), BOS (Base of Support) and comparative analysis of the moving velocity for the elderly. We analyzed the movement of COP of the body and its velocity of the elderly equipped with manual walker and gait-assistant-robot. As a result, change in COP was greater from left to right than from anterior to posterior; also, the average velocity of the movement of COP and manual walker for manual walker gait was 0.7(m/s). Therefore, it is necessary to concern more on the left-right balance and synchronization of the velocity of COP.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.4
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• pp.548-555
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• 2019

Objective: The main objective of this study was to evaluate the effect of different feeding levels of a total mixed ration silage-based diet on feed intake, total tract digestion, enteric methane emissions, and energy partitioning in two beef cattle genotypes. Methods: Six mature bulls (three Thai natives, and three Thai natives - Charolais crossbreeds) were assigned in a replicated $3{\times}3$ Latin square design, with cattle breed genotype in separate squares, three periods of 21 days, and three energy feeding above maintenance levels (1.1, 1.5, and 2.0 MEm, where MEm is metabolizable energy requirement for maintenance). Bulls were placed in a metabolic cage equipped with a ventilated head box respiration system to evaluate digestibility, record respiration gases, and determine energy balance. Results: Increasing the feeding level had no significant effect on digestibility but drastically reduced the enteric methane emission rate (p<0.05). Increasing the feeding level also significantly increased the energy retention and utilization efficiency (p<0.01). The Thai native cattle had greater enteric methane emission rate, digestibility, and energy utilization efficiency than the Charolais crossbred cattle (p<0.05). The daily metabolizable energy requirement for maintenance in Thai native cattle ($388kJ/kg\;BW^{0.75}$, where $BW^{0.75}$ is metabolic body weight) was 15% less than that in Charolais crossbred cattle ($444kJ/kg\;BW^{0.75}$). Conclusion: Our results suggested that the greater feeding level in zebu beef cattle fed above maintenance levels resulted in improved energy retention and utilization efficiency because of the reduction in enteric methane energy loss. The results also indicated higher efficiency of metabolisable energy utilization for growth and a lower energy requirement for maintenance in Bos indicus than in Bos taurus.

• Current Photovoltaic Research
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• v.6 no.3
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• pp.69-73
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• 2018

PV system is consisted with PV module, inverter and BOS(balance of system). To have robustic operation more than 20 years, the expected and guaranteed durability and reliability of products should be met. Almost components of PV system are qualified through IEC standards at test laboratory. But the qualification certificate of product does not ensure long-term nondefective operation. PV module's expected life time is nowadays more than 20 years and annual maximum power degradation ratio would be less than -1%. But the power degradation ratio is basically based on real data more than several years' record. Developing test method for ensuring annual maximum power degradation ratio is very need because there are many new products every month with new materials. In this paper, we have suggested new test method under continuous artificial light irradiation test condition for analyze expected maximum power drop ratio.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.107.2-107.2
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• 2011

태양광발전 시스템의 성능 평가는 신뢰할 수 있는 데이터의 취득 및 분석을 통하여 발전성능을 제시할 수 있다. 발전성능에 영향을 미치는 요인으로는 일사량과 온도 등의 환경적인 요인, 시스템 구성에 따른 기술적인 요인에 의해 결정될 수 있다. 특히, 시스템 구성에 의해 결정되는 기술적인 요인은 태양전지 모듈의 어레이 손실 및 BOS의 자체 손실 등을 분석하여 전체 시스템의 발전성능을 분석하여 그 성능을 평가할 수 있다. 본 논문에서는 기 설치된 태양광발전 시스템에서 취득된 데이터를 통하여 용량별, 지역별에 따른 태양광발전 시스템의 성능 분석과 손실 원인을 분석하였다. 분석결과 시스템의 성능은 환경적인 요인과 기술적인 요인에 의해 발전성능이 달라진다는 것을 확인할 수 있었다. 본 논문의 결과는 향후 태양광 발전 시스템의 성능의 기준을 제시하는 연구를 위한 사전연구로써 유용한 자료가 되리라 믿는다.