• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.111-113
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• 1994

For the analysis of characteristics of a superconducting transformer, we designed and fabricated a 5kVA superconducting transformer with two kinds of secondary winding. Using the results of the open and short tests, we calculated the parameters of its equivalent circuit. We designed also a 5kVA conventional transformer with the same design conditions as the superconducting one. The performances of the superconducting transformer were compared with the performances of the designed conventional transformer and another 5kVA distribution transformer.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.12
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• pp.2241-2248
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• 2017

The coaxial line impedance transformer that performs impedance conversion using the coupling of two or more coaxial lines of the same length is often used for impedance matching in the low frequency region due to many advantages. This paper measures the phase and magnitude characteristics of each coaxial line in a 4:1 coaxial line impedance transformer using two 100mm coaxial lines. This experiment shows that it is more effective to make the length of the auxiliary coaxial line shorter than the main coaxial line by about 5 mm in order to realize a low loss impedance transformer. In addition, it measures the transmission characteristics by directly connecting a 4:1 impedance transformer and a 1:4 impedance transformer. This experiment shows that it is effective to connect a 1pF capacitor between the ground and the outer conductor input point of the main coaxial line in order to increase the operating frequency range.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.276-280
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• 2003

This paper presents a zero voltage and zero current switching (ZVZCS) interleaving two-transistor forward converter for high input voltage and high power application. A phase shift has a disadvantage that a circulating current and RMS current stress, conduction losses of transformer and switching devices increases. Due to this circulating current and RMS current stress, conduction losses of transformer and switching devices increases. To alleviate these problems, we propose an improved interleaving two-transistor forward Zero Voltage and Zero Current Switching (ZVZCS) dc/dc converter using a tapped inductor a snubber capacitor and two snubber diodes attached at the secondary side of transformer. The proposed ZVZCS converter is verified on a 1.8kW, 5kHz experimental prototype.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.529-533
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• 2000

This paper present a new sort of multilayer piezoelectric ceramic transformer for AC-adapt. This piezoelectric transformer operates n the second thickness extensional vibration mode. The output voltage of the multilayer piezoelectric transformer was simulated using ANSYS. As results, the maximum stress appeared at the two points where one is the middle of input and the other is middle of output side in Second thickness extensional vibration mode. And output voltage was inversely decreased by increasing number of output layers.

• Journal of the Daesoon Academy of Sciences
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• v.34
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• pp.1-26
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• 2020

In Taiwanese Daoism, the Celestial Worthy of the Ninth Heaven, Responder, Thunderbolt-bearer, and Transformer of the Universe (九天應元雷聲普化天尊) is the highest deity in the Thunder Ministry. In the the Korean new religion, Daesoon Jinrihoe (大巡真理會), he is the Supreme God. However, since the Celestial Worthy of the Ninth Heaven, Responder, Thunderbolt-bearer, and Transformer of the Universe has the same name in these two traditions, it naturally leads people to wonder whether or not they can be considered the same deity. Or failing that, it could still be asked, to what extent are these two deities related? Or it could further be asked what meaning does the Celestial Worthy of the Ninth Heaven, Responder, Thunderbolt-bearer, and Transformer of the Universe have in these two religions? Anyhow, all such questions depend on first establishing a greater degree of basic clarity. Religious scripture can serve as a cornerstone in gaining such basic clarity. Scripture almost invariably contains information regarding the divine nature, divine authority, and sacrosanctity of deities reflective of what is understood by the devotees of those religions. Clues on the precise nature of these key attributes of deity-depiction can be drawn out of scriptural accounts, and as such, the research presented in this paper will begin by comparing two relevant scriptures. The representative scriptures highlighted in this paper will be The Canonical Scripture (典經) of Daesoon Jinrihoe and The Scripture of the Jade Pivot (玉樞寶經) of Zhengyi (Orthodox Unity, 正一) Daoism. These scriptures will serve as the basis for exploration and analysis of the divine attributes of the Celestial Worthy of the Ninth Heaven, Responder, Thunderbolt-bearer, and Transformer of the Universe in terms of his divine nature, divine authority, and sacrosanctity. By comparing these two scriptural accounts of his divine attributes, the similarities and differences that arise can be properly explored. This paper endeavors to clarify the ultimate purpose of 'the Celestial Worthy of the Ninth Heaven, Responder, Thunderbolt-bearer, and Transformer of the Universe.' In this paper, the first step will be an exploration of scriptural analysis. The contents of this paper is roughly divided into four sections. The first section is an exploration of the general contents of the two scriptures, including their origin, contents, and value. The second section focuses on the three main divine attributes of the Celestial Worthy of the Ninth Heaven, Responder, Thunderbolt-bearer, and Transformer of the Universe: his divine nature, divine authority, and sacrosanctity. The third section will compare the depictions of the deity in the two scriptural accounts in terms of those three attributes. Lastly, the deity's evolutionary history in both religions is shown and compared and final remarks are made on the contemporary value of the Celestial Worthy of the Ninth Heaven, Responder, Thunderbolt-bearer, and Transformer of the Universe.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.3
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• pp.243-247
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• 2005

The Different-volume- V-connection transformer is known as an electric power source that can supply 3-phase electric power and single-phase electric power at the same time. Usually, we use two single-phase transformers that have different volumes. In this paper, we propose the use of a 3-phase 5-leg transformer with the different-volume- V-connection. And, we examine the magnetic properties of the 5-leg core model with the different-volume- V-connection. The magnetic properties of cores with the different-volume- V-connection are compared with those with the delta-connection. In order to express the magnetic anisotropy of the core materials and to calculate the iron loss directly, the two-dimensional vector magnetic property is considered with the E&SS modeling in the simulation.

• Journal of Power Electronics
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• v.8 no.3
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• pp.217-227
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• 2008

The electric power subsystems (EPS) of most remote sensing satellites consist of a solar array as a source of energy, a storage battery, a power management and control (PMC) unit and a charge equalization unit (CEU) for the storage battery. The PMC and CEU use high frequency transformers in their power modules. This paper presents a design, implementation and testing results of a high frequency transformer for the EPS of satellite applications. Two approaches are used in the design process of the transformer based on the pre-determined transformer specifications. The transformer is designed based on an ETD 29 ferrite core. The implemented transformer consists of one center-tapped primary coil with eleven center-tapped secondary coils. The offline calculation results and measured values of R, L for transformer coils are convergence. A test circuit for measuring the transformer parameters like voltage, current and B-H hysteresis was implemented and applied. The test results confirm that the voltage waveforms of both primary and secondary coils were as desired. No overlapping occurred between the control signal and the transformer, which was not saturated during testing even during a short circuit test of the secondary channels. The dynamic B-H loop characteristics of the used transformer cores were measured. The sample test results are given in this paper.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.6
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• pp.1166-1173
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• 2009

In this paper, we studied on the power amplifier which has the output of the optimal to 100MHz-2GHz band. Optimal output power match was fabricated using the two types; one is the linear tapering and the other is the impedance transformer. In the case of output power match using linear tapering, output power was 35.35dBm at 2GHz and 31.41dBm at 100MHz. The other case of output match using impedance transformer, output power was 34.8dBm at 2GHz and 33.25dBm at 100MHz. Comparison of the results in the two cases, impedance transformer type present the improved results by l.84dB of output power.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.7
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• pp.375-381
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• 2004

This paper describes a three-winding transformer protective relaying algorithm based on the ratio of increments of flux linkages (RIFL). To minimize the approximation errors, the algorithm uses integration approximation. The RIFL of the two windings is equal to the turns ratio for all operating conditions except for an internal fault. For a single-phase and three-phase transformer containing the wye-connected windings, the increments of flux linkages (IFL) are calculated. For a three-phase transformer containing the delta-connected windings, the difference of IFL between the two phases are calculated to use the line currents, because the winding currents are practically unavailable. Their ratios are compared with the turns ratio. The comparative study between the proposed and differential approximation methods was conducted. The test results show that the algorithm can reduce the errors resulting from the conventional methods.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.10
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• pp.630-634
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• 2016

In this paper, we analyzed the power consumption and the accumulated energy in HTSC (high-TC superconducting elements) according to the resistance of HTSC element and the winding current of transformer type SFCL (superconducting fault current limiter) using double quench. For the analysis, two different inductances of the one secondary winding among two secondary windings comprising the transformer type SFCL were selected and the short-circuit tests were carried out. The consumed power and the accumulated energy in HTSC element connected into the secondary winding with larger inductance were analyzed to be larger compared to the one connected into the secondary winding with lower inductance.