• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.237-240
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• 2004

For the paralleled operation of DC/DC converters, the current sharing between each modules is the most important for the reliability of the power system. Interleaving method is commonly used with many paralleling schemes for the reduction of the ripple in the output voltage of paralleled converters and there are many commercial IC for interleaving application appliable. But for all of them, it is impossible to detect the number of module in operating and then change the phase of them automatically. In this paper, a novel paralleling method is proposed for the converter parallel operation, which detects the number of modules in active and sets the phases of PWM signals applied to each modules autonomously. This can greatly improve the output voltage ripple and reliability of the system. The expandibility of modular number can be done very easily by just adding several parts.

• Journal of Power Electronics
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• v.14 no.4
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• pp.788-795
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• 2014

This paper demonstrates the dynamic behaviors of paralleled high power IGBTs using trench and fieldstop technologies. Four IGBTs are paralleled and standard deviation is adopted to represent the imbalance. Experiments are conducted under three different operation conditions and at different temperatures ranging from $-25^{\circ}C$ to $125^{\circ}C$. The experimental results show that operation at very low and very high temperatures usually aggravates the switching behaviors. There is a trade-off between the balance and the losses at low temperatures. These results can help in the design of heat sinks in paralleling applications confronting very low temperatures.

• Aerospace Engineering and Technology
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• v.2 no.1
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• pp.89-95
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• 2003

In this study, we examine a large number of methods for paralleling power converter, many current control techniques and the cause and solutions of the current unbalance that occurs at the application of a paralleling scheme. For each paralleling schemes, we inspect the merits and drawbacks and analyze the characteristics of each current control methods. With previously examined and analyzed results, we develop a modularizing method that can be available for unregulated bus system. And finally, we verify the possibility of the chosen modularizing method by executing simulation and performing prototype experiment.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.400-402
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• 2008

A new interleaved forward converter, adopting series-input parallel-output structure with a common transformer reset circuit, is proposed in this paper. Series-input structure distributes the voltage stress on switches, which makes it suitable for high input voltage application. Paralleling output stage with an interleaving technique enables the circuit handle large output current and reduces filter size. In addition, since two forward converters share one active-clamp circuit for the transformer reset, its primary structure is simplified. All these features make the proposed converter promising for high input voltage applications with high efficiency and simple structure.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1015-1017
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• 2002

This is the study on static excitation system of synchronous generator of large capacity in new model, which was developed by KEPRI using triple redundant digital method, associate three bridges of thyristor phase controlled rectifier. This paper will discuss the design conception and the application results of system which includes the power control devices(thyristors, GTO) and power excitation potential transformer. The multi-paralleling thyristor bridge converters of N+1 method have firing circuit. The initial product manufactured by proposed design in the study is in commercial operation, completing installation and commissioning in 400MW Thermal Power Plant. The performance test is done in practical technique.

• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.220-222
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• 2007

With the wide spread of direct current (DC) electric railroads in Korea, the stray currents or leakage currents from negative return rails become a pending problem to the safety of nearby underground infrastructures. The most widely used mitigation method for this interference is the stray current drainage method, which connects the underground metallic structures to the rails with diodes (polarized drainage) or thyristor (forced drainage). Although this method inherently possesses some drawbacks, its cost effectiveness and efficiency to protect the interfered structures has been the main reason for the wide adoption. In this paper, we show the field test results for the application of stray current drainage system to a city gas pipeline paralleling a depot area of a metropolitan rapid transit system. The process for optimal positioning is briefly illustrated. The effectiveness of constant voltage, constant current, and constant potential drainage schemes was also described.

• Journal of Korean Society of Rural Planning
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• v.10 no.1 s.22
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• pp.41-55
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• 2004

The purpose of this study is to investigate a causal relationship between the mode of production and change of rural society. While dominant theories of social change have stressed variation of contingencies and periodical contexts, this theoretical paper drives a new insight paralleling diverse theoretical arguments of each mode of production with rural and urban changes. Investigating the drifts of intellectual ideologies of the mode of production, we get through diverse paradigm shifts of the production accumulation and its trigger effects on rural change. More specifically, the present study investigates change of rural society by way of investigating such fluctuations of societal changes as ancient society, slavery society, feudal society, industrial society, post-industrial society, and information society. We find that transportation and communication technologies have had a key role in the changes, however, the effects of the technologies on social changes have been different between rural- and urban-society. While we take it for granted that flexible accumulation in post-industrial society and time-space compression and informatization in information society will reduce developmental gap between rural- and urban-society, we also found that there have been big differences of actual application of the technologies between theory and reality in each era of mode of production.

• The Journal of the Korea Contents Association
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• v.21 no.4
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• pp.723-733
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• 2021

'Reboot' and 'Homage' are using as creative techniques in traditional storytelling media fields such as movies or dramas, but the possibility of expanding the transmedia story world has not yet been presented. This study was written to present a new concept of transmedia story world expansion type using the 'Reboot' and 'Homage' methods. 'Reboot' and 'Homage' are typical storytelling methods of K-POP idol groups that need to develop content. I selected , , and , which have built their story world, and examined both the narrative creation section and the marketing application section. The result of the study is as follows. First, EXO is an example of a reboot case. They set the original set as 'past' and insert the new storylines. Second, BTS is an example of a character's reboot. They built a story world by paralleling 'Idol BTS' and 'Character BTS'. Third, Wanna One is an example of the original story world's homage. They reorganize the story world of and attracting the attention of the existing audience. Fourth, BTS is an example of other media homage which reinterprets the meaning of BTS characters and story world by using the meaning of classic works.