• KIPE Magazine
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• v.19 no.5
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• pp.47-52
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• 2014

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.4
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• pp.100-105
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• 1998

This paper proposes a new control strategy of bidirectional uninterruptible power supply (UPS) with the performance of active power filter which compensates the harmonics and reactive power. With only one power stage, it is working simultaneously as the AC/DC rectifier/battery charger and DC/AC inverter to the operation of battery charging or back-up power supplying. Therefore the operation of the proposed system can be divided into the modes, such as the active power filter mode and the battery back-up power mode. And a novel closed-loop control strategy is used to calculate the reference current. The performance of the proposed 5[kVA] system is verified by the simulation and experimental results.

• Electric Engineers Magazine
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• v.177 no.5
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• pp.48-53
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• 1997

전력전자기술 발전에 따라 최근의 전기설비에서는 FA 및 OA용 전원은 정보통신용 전원으로 무정전 전원장치가 필수적으로 시설되고 있다. 또한 성에너지를 위한 전동기 가변속 구동장치가 많이 채택되고 있다.

• JOURNAL OF ELECTRICAL WORLD
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• no.2 s.206
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• pp.2-6
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• 1994

상공자원부에서는 산업의 원동력이자 국민생활의 기본 에너지인 전기의 품질을 최고급 수준으로 향상시켜 산업의 경쟁력을 뒷받침하고, 국민 모두가 밝고 풍요로운 문화생활을 향유하는데 불편이 없도록 하기 위해서 전기품질향상 三無運動(무정전, 무변전압, 무변주파수) 계획을 수립하고, 이 운동에 대한 전력산업 관계자 여러분의 적극적인 참여와 국민 모두의 협조를 바라는 뜻에서 그 계획을 소개하고자 한다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.5
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• pp.18-24
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• 2006

This paper proposed UPS system parallel connected in battery and ultracapacitor to compensate instantaneous voltage drop. Ultracapacitor parallel connected with battery compensate instantaneous voltage drop at failure and it's reduced the voltage regulation of output voltage. We are produced for fast instantaneous voltage drop compensation of ultracapacitor at UPS system and experiments are achieved. Experimental result was verified that the ultracapacitor indicated the fast compensation characteristics and regulation of the output voltage satisfied within 5[%] by using ultracapacitor.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.685-688
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• 2006

A single-phase uninterruptible power supply system suitable for a SMES unit is proposed to achieve a simple circuit configuration and higher system reliability. It reduces the number of switching devices by applying a common-arm scheme. Operational principles to normal, stored-energy, and bypass mode are discussed in detail. Eliminating some of the switches or substituting passive components for active switches generally increases the sophistication and reduces degree of freedom in control strategy. However, the high-performance digital controller ran execute the complicated control task with no additional cost. The validity of the proposed UPS system will be verified by a computer-aided simulation.

• Korean Journal of Animal Reproduction
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• v.27 no.1
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• pp.61-67
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• 2003

This study was conducted to investigate the effect of infusion of sterile boar and their semen as pregnancy antigen factor for improvement of production in gilts. We observed 160 gilts between 7 to 8 months of age that were divided into 4 treatment groups vie. A group-epidimetomized boar, B group-no sperm semen infusion, C group-vasectomized boar, and D group-control in a completely randomized design. The number of total pigs born(NT) of A, B, C, and D groups were 10.05, 10.44, 11.63, and 9.97 pigs, respectively(P<0.05). And the NT of C g.cup was the highest among treatment. The number of live pigs born(NB) was similar to NT The NB of C group (10.70) was higher than that of A(9.12) and control(9.11)(P<0.05). However, there was not significant between B and C groups. The progesterone concentration of C group was the highest compare to other group at the 6th day after breeding. However, the progesterone concentration of C was lower than other groups after 8th day. There were not significant among cortisol of A, B, C and D groups. According of the results of this study, the infusion with vasectomized boar and semen at estrus before gestation can be improved reproductive efficiency because of more litter size in gilts.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06a
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• pp.236-238
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• 2012

본 논문은 저전력 데이터센터에 사용되는 DC 서버를 위한 고효율 DC UPS 결합형 전원분배장치의 구현과 설계에 관한 내용이다. 본 논문이 제안한 노드 준위 UPS 결합형 전원분배장치의 전력효율은 96%에 이르며 저전력 볼륨 서버의 전원공급장치(PSU)와 UPS를 대체할 수 있는 기술이다.

• Proceedings of the KIPE Conference
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• 2011.11a
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• pp.245-246
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• 2011

전력계통에서 발생되는 전기의 품질 저하문제는 순시적 전압강하 등 전압의 크기문제 뿐 아니라 고조파 또한 상당부분을 차지하고 있으며, 그 피해 또한 매우 심각하게 나타난다. 이러한 피해를 최소화하기 위한 일련의 방법으로 UPS 시스템을 사용하게 되는데 이 UPS 시스템을 사용하는데 있어서 빠르게 에러를 검출하는 방법을 필요로 한다. 이 논문에서는 그 방법에 대해 연구해 보도록 한다.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.300-302
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• 1996

In this paper a new series-parallel compensated uninterruptible power supply is proposed. Its series compensator shapes input current to sinusoid. The power handled by series compensator is only a quarter of ratings. And parallel compensator delivers sinusoidal voltage to nonlinear load. The parallel compensator is backedup with battery. This system has capabilities of power line conditioner and backup power with reduced size.