• Journal of information and communication convergence engineering
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• 제5권2호
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• pp.150-154
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• 2007

Transponders of RFID system are classified as active or passive depending on the type of power supply they use. In passive transponders the data carrier has to obtain its power from the induced voltage. The induced voltage is converted into direct current using a low loss bridge rectifier and then smoothed. In practice, the induced voltage in the transponder coil is variable according to the coupling coefficient k and the load resistance ($R_L$). Therefore, the rectified voltage is unstable and the transponder of RFID is unstable sometimes. In this paper, a voltage-dependent shunt resistor ($R_s$) circuits are designed and inserted in parallel with the load resistance of RFID transponder in order to improve the stability of power.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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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.

• Journal of Power Electronics
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• 제8권1호
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• pp.1-9
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• 2008

This paper presents the design and analysis of a new input AC current wave shaping AC-DC converter for cost effective harmonic mitigation under varying loads. The proposed converter consists of a delta-polygon connected autotransformer based twelve-pulse AC-DC converter and a small rating passive shunt filter tuned at $11^{th}$ harmonic frequency. The proposed AC-DC converter eliminates the most dominant $5^{th},\;7^{th}$ and $11^{th}$ harmonics and reduces higher order harmonics; thereby, resulting in an improved power quality at AC mains. Moreover, the design of the autotransformer is modified to make it suitable for retrofit applications, where presently a 6-pulse diode bridge rectifier is used. To validate the proposed approach, various power quality indices are presented under varying loads. Experimental results obtained on the developed converter are given to validate the model and design of the proposed converter.

• 한국산학기술학회논문지
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• 제2권2호
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• pp.11-18
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• 2001

본 연구에서는 의료용 X선 발생기의 고전압 발생장치를 설계하는 방법을 제시한다. 고전압의 발생을 위해 인버터를 사용하였다. 또한 라인필터회로, 정류회로, 펄스 복 변조 제어회로, 전 브리지 구동회로, 고전압 트랜스, 고전압 정류회로를 설계 제작하였다. 본 논문에서 제시된 설계 방법에 의해 스위칭 주파수 40 KHz인 고전압 발생장치를 제작·실험하여 가변전압 0∼620 V. 가변전류 50 ∼500 mA를 얻었다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.391-393
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• 2008

A modified boost converter with magnetic coupling is presented to reduce the reverse recovery loss while maintaining low conduction loss of the rectifiers. By utilizing a coupled inductor and a set of diodes, the current passing the boost rectifier is transferred to an auxiliary loop before turn-off, allowing low di/dt for reduced recovery loss. Moreover, the boost inductor is brought inside the bridge rectifier to reduce conduction loss by decreasing the number of conducting diodes during switch turn-off. Experimental results of a 500W prototype are provided to verify the increase in efficiency and validity of the proposed converter.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 B
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• pp.618-620
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• 1999

The owner of metallic structures has a burden of responsibility for the protection of corrosion and the prevention against big accident such as gas explosion or collapse of bridge and building and so on. So, he has been spent the money and the time for corrosion monitoring and analysis of measuring data. Therefore, KERI(Korea Electrotechnology Research Institute) has developed the real-time wireless remote corrosion monitoring system using by TRS(Trunked Radio System). The results of development for corrosion monitoring system are described briefly. Especially, the interfacing technology between the server and rectifier introduced in this paper.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.395-398
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• 2002

This paper presents generalized small-signal models for complementary driven double-ended isolated converters. The proposed small-signal models include the effect of the parasitic resistances, which have dominant influence on the damping of the secondary Power stage double-pole. To confirm the validity of the new models, an asymmetrical half-bridge converter with confer-taped rectifier and a forward-flyback converter with current doubler rectifier were built, and their performance were compared with the theoretical prediction.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 춘계학술대회 논문집
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• pp.328-335
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• 1999

Three phase full bridge rectifier has been used to obtain dc voltage from three phase ac voltage source. The rectifier system has drawbacks that power factor is low and power flow is unidirectional. Therefore, when dc voltage increases due to regeneration of power the dynamic resister for dissipation of regeneration power must be installed. But three phase PWM converter can be controlled to operate with unity power factor and bidirectional power flow. Therefore when the PWM converter is used as do supply system, the dissipating resistor is not necessary. On this thesis, in order to design a controller having good performance, the hee phase PWM converter is completely modeled by using circuit DQ-transformation and thus a general and simple instructive equivalent circuit is obtained; the inductor set becomes a second order gyrator-coupled system and three phase inverter becomes a transformer as well. Under given phase angle(${\alpha}$) and modulation index(MI) of the three phase inverter, the dc and ac characteristics are obtained by analysis of the transformed equivalent circuit The validity of the equivalent circuit is confirmed through PSPICE simulation. And based on the dc and ac characteristics a controller with unity power factor is proposed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1401-1403
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• 2005

This paper presents generalized small-signal models for asymmetrically-driven double-ended dc-to-dc converters. The proposed small-signal models include the effects of the parasitic resistances, which have dominant influence on the damping of the secondary power stage double-pole. To confirm the validity of new models, an asymmetrical half-bridge converter with center-taped rectifier and a forward-flyback converter with current doubler rectifier were built, and their performances were compared with the theoretical predictions.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2018년도 추계학술대회
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• pp.59-61
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• 2018

본 논문에서는 입력전류를 센싱 받지 않아도 역률 보상을 하는 새로운 단일단 브리지리스 AC-DC컨버터를 제안한다. 제안하는 컨버터의 스위치는 전구간에서 ZVS(Zero Voltage Switching) 턴 온을 성취하며, 다이오드는 전구간에서 ZCS(Zero Current Switching) 턴 오프를 성취한다. 제안하는 컨버터의 넓은 범위의 출력전압 제어와 간단한 전력 제어를 위해 SDAB(Semi-Dual Active Bridge)기반의 모듈레이션 기법을 적용하였다. 1kW급 50kHz의 스위칭 주파수를 갖는 시작품을 통해 본 논문의 타당성을 검증하였다.