• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
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• pp.432-434
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• 2006

We investigated the quench characteristics of a flux-lock type superconducting fault current limiter (SFCL) according to the number of the superconducting elements at the subtractive polarity winding of a transformer. The flux-lock type SFCL consists of the transformer with a primary winding and two secondary windings connected in parallel, and the superconducting element was connected with secondary winding in series, respectively. The applied voltage at that tin was 200V. when two superconducting elements of the secondary winding was connected in parallel, the peak lie current increased up to 99A, while that flowing in a superconducting element in conventional flux-lock type SFCL showed 50A under the same conditions, the impedance of secondary winding under the same situation showed the opposite behavior. This enabled the parallel structure to be easy to increase the capacity of power system, in the meantime, The quench between two superconducting elements in the SFCL with two secondary windings connected in parallel was achieved simultaneously. While the quench-starting point was slightly different in the SFCL with two superconducting elements connected in series. We found that the parallel connection between the secondary windings increased the power capacity and let quench characteristics improve through their mutual linkage.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 추계학술대회
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• pp.27-28
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• 2017

In this paper, design method for a high frequency transformer with high insulation is presented. The insulation performance of the high frequency transformer is determined by the distance between primary and secondary windings, and the characteristics of dielectric material. For the voltage strength safty, a high frequency transformer model is designed. By using computer simulation, the transformer model is evaluated.

• Journal of Power Electronics
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• 제14권6호
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• pp.1093-1099
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• 2014

This paper proposes a power conversion topology involving a multi-winding transformer and converters. The fundamental idea is described with circuit diagrams, and the voltage output of the proposed topology is analyzed mathematically. The effectiveness of the topology is discussed with test results from a small-scale power conversion system. When conventional hardware consisting of two-level converters and a transformer is employed, multi-level voltage outputs can be applied to the transformer windings by the proposed method.

• 전력전자학회논문지
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• 제20권3호
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• pp.255-261
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• 2015

An analysis of the interleaving effect for the secondary winding distribution of a toroidal transformer is presented in this paper. The equations to calculate the leakage inductance of the toroidal transformer are derived using MMF diagrams for the different secondary winding distributions. The simulation and experimental results are provided to show the validity of the theoretical calculation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.493-495
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• 1995

Recently, as power transformer capacity is getting larger, vibration noise of transformer would be large and unexpected failuare of transformer give enormous economic loses, So we aquaire vibration signal, which is maked from transformer windings, core that are airtight out box with in insulation oil, and out box. Also we are fixed rated voltage and changing load current, analyize frequency domain of each vibration signals.

• 대한전기학회논문지:전력기술부문A
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• 제52권11호
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• pp.655-660
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• 2003

This paper describes a transformer protective relaying algorithm based on the ratio of increments of flux linkages (RIFL) of the primary and secondary windings. The algorithm uses integration approximation. The RIFL is equal to the turns ratio for all operating conditions except for an internal fault. For a single-phase transformer and a Y-Y transformer, the increments of flux linkages (IFL) are calculated. For a Y-$\Delta$ transformer, the difference of IFL are calculated to use the line currents rather than the delta winding currents, which are unavailable. Their ratios are compared with the turns ratio. The comparative study between the proposed and conventional differentiation approximation methods was conducted. The test results show that the algorithm reduces the approximation errors of the conventional methods.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.258-261
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• 2000

A non-contact battery charger which transfers energy using magnetic field has a difficulty with a feed-back control due to the interaction between the power and signal processing This paper proposes an effective method which uses auxiliary windings of transformer as signal path and copes with cross-talk using the MOSFET ringing phenomenon and ceramic filter. The power stage is half-bridge series resonant converter. Design procedure and experimental verification are presented.

• 한국조명전기설비학회지:조명전기설비
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• 제5권3호
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• pp.72-77
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• 1991

In a large power transformer, insulating oil is forced to circulate for cooling the heat generated by the losses within windings and core. When insulating oil flows and rubs against various materials, such as insulating paper or core, the electrostatic charges are separated at the interface of the oil and the solid material. This paper considers the streaming electrification of various materials used in the transformer. In this study, we show that a solid material such as paper is negatively charged. On the other hand, a solid material such as core is positively charged.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.592-594
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• 1998

In order to analysis high frequency interference conduction in transformer, this paper constructs a equivalent network based on P.I. Fergested transformers physical model. A method of calculating self and mutual leakage inductance of windings sections is presented and a calculating example is given.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.476-479
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• 2002

The proposed DC/DC converter employs a pair of neighboring printed-circuit-board windings as a coreless transformer Thus, the proposed DC/DC converter can be fabricated In an ultra low-profile fashion. The performance of the proposed low-profile DC/DC converter is confirmed with experiments on a prototype converter that delivers 58W of power at the maximum efficiency of $84\%$.