• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.5
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• pp.492-500
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• 2013

A balanced forward-flyback converter for high efficiency and high power factor using a foward and flyback converter topologies is proposed in this paper. The conventional AC/DC flyback converter can achieve a good power factor but it has the high offset current through the transformer magnetizing inductor, which results in a large core loss and low power conversion efficiency. And, the conventional forward converter can achieve the good power conversion efficiency with the aid of the low core loss but the input current dead zone near zero cross AC input voltage deteriorates the power factor. On the other hand, since the proposed converter can operate as the forward and flyback converters during switch turn-on and turn-off periods, respectively, it cannot only perform the power transfer during an entire switching period but also achieve the high power factor due to the flyback operation. Moreover, since the current balanced capacitor can minimize the offset current through the transformer magnetizing inductor regardless of the AC input voltage, the core loss and volume of the transformer can be minimized. Therefore, the proposed converter features a high efficiency and high power factor. To confirm the validity of the proposed converter, theoretical analysis and experimental results from a prototype of 24W LED driver are presented.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1999.11a
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• pp.99-102
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• 1999

The object of this paper is design and to make a high efficiency magnetic ballast for high pressure sodium lamp. The results show the efficiency is 10[%] up compared with standard ballast in best case.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.10
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• pp.501-507
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• 2001

In this paper, new high-efficiency zero voltage switching (ZVS) AC-DC boost converter is proposed to achieve power factor correction by simplifing energy recovery circuit. A lot of high power factor correction circuits have been proposed and applied to increase input power factor and efficiency. Most of these circuits may obtain unity power factor and achieve sinusoidal current waveform with zero voltage or/and zero current switching. However, it is difficult for them to obtain low cost, small size, low weight, and low noise. The topology proposed to improve these problems can compact the devices in circuit and can achieve high efficiency ZVS AC-DC boost converter. Simulation and experimental results show that this topology is capable of obtaining high power factor and increasing the efficiency of the system.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.188-191
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• 2009

A high efficiency deep blue phosphorescent organic light-emitting diode (PHOLED) was developed using a new wide triplet bandgap host material (PPO1) with a phenylcarbazole and a phosphine oxide unit. The wide triplet bandgap host material was synthesized by a phosphornation reaction of 2-bromo-Nphenylcarbazole with chlorodiphenylphosphine. A deep blue emitting phosphorescent dopant, tris((3,5-difluoro-4-cyanophenyl)pyridine)iridium (FCNIr), was doped into the PPO1 host and a high quantum efficiency of 17.1 % and a current efficiency of 19.5 cd/A with a color coordinate of (0.14,0.15) were achieved in the blue PHOLED. The quantum efficiency of the deep blue PHOLED was better than any other quantum efficiency value reported up to now.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.88-88
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• 2012

High efficiency thin film photovoltaic device technology is reviewed. At present market situation, the industrial players of thin film technologies have to confront the great recession and need to change their market strategies and find technical alternatives again. Most recent technology trends and technical or industrial progress for Silicon thin film and CIGS are introduced and common interests for high efficiency and reliability are discussed.

• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.803-808
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• 2017

Minimum Energy Performance Standard(MEPS) has been adapted in Korea since 2008. The efficiency standard of variable speed motors is scheduled for publication shortly. In this paper, author reviews the technical trends associated with a high efficient electric motors by reference to research papers, and reviews the research direction to prepare for IE5. This paper provides an overview of high efficiency motors. Various applications have been covered.

• Proceedings of the KIEE Conference
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• 2007.11b
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• pp.273-275
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• 2007

This paper analyzes the customer behavior on high efficiency inverter program in terms of rebate levels. The importance of high efficiency DSM programs has been more and more increased after deregulation. Especially, the inverter program is one of the most high efficiency DSM programs, so this paper presents proper rebate levels in terms of both participants and non-participants to promote diffusion of the inverters.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.180-182
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• 2005

This paper analyzes the customer behavior on high efficiency motor programs from three angles, that is, rebates, electricity rates and the cost of measures. After deregulation, the importance of high efficiency DSM programs has been more and more increased. Especially, the motor program is one of the most high efficiency DSM program, so it Is needed the policy to promote the motor programs diffusion.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2000.11a
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• pp.177-193
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• 2000

In foreign countries, high-efficiency electric machineries have been developed in view of cost reduction, environmental issues, energy conservation etc. Especially they focus on developing energy conservation measures and demand-side management. Thus, patent application and secure of patent claims are on the rise as important issues in this field. In this paper, we analyzed patent application trends about inverters, ac/dc converters, reactive power control equipments, high-efficiency transformers and electric ballasts among high-efficiency electric machineries. First, we analyzed general technology trends, and constructed patent technology data. Second, we graphed patent application trends in terms of application years, assignees and nations.

• Proceedings of the KIEE Conference
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• summer
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• pp.674-676
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• 2004

This paper analyzes the customer behavior on high efficiency inverter program from three angles, that is, rebates, electricity rates and the cost of measures. After deregulation, the importance of high efficiency DSM programs has been more and more increased. Especially, the inverter program is one of the most high efficiency DSM program, so it is needed the policy to promote the inverter program diffusion.