• 한국진공학회지
• /
• 제19권3호
• /
• pp.230-235
• /
• 2010

본 논문에서는 TCP-CVD를 이용하여 실리콘 산화막 형성에서 산화막의 특성에 영향을 미치는 전력, 가스 유량, 기판 바이어스 등의 공정조건에 따른 증착률과 굴절률을 제어하고자 한다. 그 결과 기판온도 300 [$^{\circ}C$], $SiH_4$ : $O_2$=50 : 100 [sccm], TCP power 1 [kW], 기판 바이어스 200 [W]를 인가한 조건에서 매우 우수한 균일도(<1 [%]) 및 증착률(0.28 [${\mu}m$/min])과 굴절률 (1.4610-1.4621)을 나타내는 안정된 $SiO_2$ 산화박막을 제조할 수 있었다.

• Journal of Power Electronics
• /
• 제15권1호
• /
• pp.1-9
• /
• 2015

This study presents a novel transformer isolated parallel connected quasi Z-source (qZ-source) full-bridge DC-DC converter that uses a coupled inductor in both the qZ-source network and output filter inductor. Unlike traditional voltage-fed or current-fed converters, the proposed converter can be open- and short-circuited without damaging switching devices. Therefore, the desired buck and boost functions can be achieved and converter reliability can be significantly improved. All the bulky inductors in the qZ-source network and output filter can also be minimized with the proposed inductor structures. A 4 kW prototype DC-DC converter is built and tested to verify the performance of the proposed converter.

• 전력전자학회논문지
• /
• 제19권5호
• /
• pp.440-449
• /
• 2014

This study proposes an LLC series resonant converter with a current doubler using a coupled inductor as a rectification circuit for the secondary side. The current doubler circuit is generally used for a high-voltage input and low-voltage output circuit to obtain high efficiency with small transformer turn ratio. However, an inductive circuit is not generally used in the secondary side of an LLC series resonant converter. If inductive components exist on the secondary side, the resonant characteristics are changed through the secondary inductive circuit. Mathematical analysis shows that the secondary-side current doubler with coupled inductor is not affected by the resonant characteristic of the primary LLC if leakage inductance occurs in the coupled inductor. Results of the analysis are proven by simulation; an experiment is also conducted for the proposed circuit.

• 전력전자학회논문지
• /
• 제23권3호
• /
• pp.208-216
• /
• 2018

In this paper, an LLC resonant converter employing two coupled inductors on the secondary side of the converter is proposed. The conventional LLC converter exhibits serious power loss during secondary winding of the transformer because of generation of tremendous output current ripples. To overcome this problem, an LLC resonant converter with a current doubler as a rectifying circuit was recently proposed. However, the current-doubler rectifying circuit requires coupled inductors with a high coupling ratio to retain the designed resonance characteristics. Therefore, an additional hardware filter is required at the output stage to address large output current ripples. Additional design procedures are also necessary because the inductance component of the added filter affects the designed resonant network. To solve this issue, an LLC resonant converter employing two coupled inductors is proposed in this paper. Mathematical analysis shows that the proposed secondary-side current-doubler circuit does not affect the designed resonance characteristics. The operating principles and theoretical analyses are proven through a simulation and experiments with a 54 V/28 A prototype.

• 센서학회지
• /
• 제11권3호
• /
• pp.132-137
• /
• 2002

본 연구에서는 온도에 따른 압전특성이 매우 안정적인 $LiTaO_3$ ($x-112^{\circ}$ y) 단결정을 이용하여 압전변압기를 제작하고 그 특성을 분석하였다. 제작시 $LiTaO_3$ 단결정의 변환효율이 낮은 단점을 보완하기 위해 Lame'-mode를 이용하여 길이와 폭의 비가 2:1인 압전변압기를 제작하고 PSpice를 이용하여 진동 모드 해석, 입력전압에 따른 출력전압특성 및 진동속도특성을 분석하였다. 제작한 압전변압기는 길이방향의 제 2차 고조파 주파수와 폭방향의 기본공진주파수가 결합된 290.83[kHz]에서 입력전압에 대한 최대출력전압이 나타났으며, 약 10배 정도의 승압비를 얻을 수 있었다.

• Journal of Power Electronics
• /
• 제13권2호
• /
• pp.206-213
• /
• 2013

In this paper, an improved passive snubber is investigated in a single-phase single-stage full-bridge boost power factor correction (PFC) converter, by which the voltage spike across primary side of the power transformer can be suppressed and the absorbed energy can be transferred to the output side. When compared with the basic passive snubber, the two single-inductors are replaced by a coupled-inductor in the improved snubber. As a result, synchronous resonances in the snubber can be achieved, which can avoid the unbalance of the voltage and current in the snubber. The operational principle of the improved passive snubber is analyzed in detail based on a single-phase PFC converter, and the design considerations of both the snubber and the coupled-inductor are given. Finally, a laboratory-made prototype is built, and the experimental results verify the feasibility of the proposed method and the validity of the theoretical analysis and design method.

• 제어로봇시스템학회논문지
• /
• 제20권2호
• /
• pp.143-148
• /
• 2014

Conventional wireless power transfer methods based on coupled magnetic fields need a complex winding structure on the surface of the energy transfer and shows poor efficiency near metal objects due to the eddy current effect. In this study, to mitigate these problems, we investigate an electric field-coupled power transmission system, which is less prone to metal object problems and EMI. Because of the fundamental physical limit in the size of link capacitances, a half-bridge converter with an impedance matching transformer is proposed and the design procedure is derived to provide a soft-switching scheme. Hardware implementation shows that the proposed scheme with a pair of 10cm by 10cm copper plate can power a 1.4W USB FAN in a separation of 0.2mm by using insulating paper when driven by 227 kHz gate pulse.

• 한국전자파학회논문지
• /
• 제9권3호
• /
• pp.399-409
• /
• 1998

본 논문에서는 CATV 시스템용 약결합형 신호분기기에 대한 광대역 설계이론을 설명하고, 전송선로의 임피던스 정합법을 제안하였다. 위의 이론과 방법에 의해 제작된 약결합형 신호분기기는 종래의 약결합형 신호분기기에 비해 주파수특성이 매우 향상되었다. 따라서, 약결합형 신호분기기의 대역폭은 5-2000 MHz로 확대되었다. 또한, 실제 회로에서 변성기를 구성하는 코일의 권선수는 정수가 아니라 0.9, 1. 1.9, 2, 2.9 등임을 밝혔다. 나아 가서, 실제로 제작된 약결합형 신호분기기의 주파수 특성이 이론치와 잘 일치함을 보임으로써, 제안한 설계이론 및 전송선로의 임피던스 정합법의 타당성이 입증되었다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2006년도 추계학술대회 논문집 광주전남지부
• /
• pp.81-86
• /
• 2006

In this paper, we designed the cylindrical type light source that had a electromagnetic principle of inductively coupled plasma, and measured its electrical-optical properties. Using the principle of transformer, electrically equivalent circuit of cylindrical type light source was analyzed. According to the parameters of electromagnetic induction which were diameter of coil with 0.3~1.2 mm, number of turns with 4~12 turns, distance with 40~120 mm and RF power with 10~150 W, the electrical and optical properties were measured. When diameter of coil was 0.3 mm, number of turns was 8 turns and distance was 40 mm, the highest brightness of 29,730 $cd/m^2$ was shown with RF power 150 W. The relationship between electromagnetic induction and plasma discharges was shown by mode transition from E-mode to H-mode.

• Progress in Superconductivity
• /
• 제5권2호
• /
• pp.128-131
• /
• 2004

The resistive superconducting fault current limiters (SFCLs) are very attractive devices for the electric power network. But they have some serious problems when the YBCO thin films were used for the current limiting materials due to the in homogeneities caused by manufacturing process. When the YBCO films have some inhomogeneities, simultaneous quenches are difficult to achieve when the fault current limiting units are connected in series for increasing operating voltage ratings. Magnetic field application is one of the prospective way of inducing simultaneous quenches far the series-connected resistive FCL components. Magnetic field was typically generated by the fault current thorough a coil, which is connected to components of the fault current limiter in series, leaving the problem, which provides significant inductance to the power line and suppresses critical current density of the superconducting components. In this article we investigated the possible application of the protective current transformer (p-CT), which is available current source to the magnetic coil. This system inductively coupled to the circuit, therefore, remarkably reducing impedance to the circuit. The current by the protective current transformer was directly fed to the coil, generating magnetic field large enough to reduce critical current density of the components. This successfully induced simultaneous quenches of the series-connected resistive FCL components.