• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
• /
• pp.425-429
• /
• 2004

A new multi-level type energy recovery sustaining driver for AC PDP(Plasma Display Panel) is proposed in this paper. The multi-level driver has been developed to reduce the voltage stress on switching elements. Comparing the proposed driver with the conventional multi-level driver, 4 switching elements, 4 diodes, and two auxiliary capacitors are eliminated in the viewpoint of circuit structure. Moreover, the voltage stress on switching elements is more reduced and the sustain period is extended. To verify the validity of the proposed energy recovery circuit, computer simulations using PSpice program are carried out.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 하계학술대회 논문집 F
• /
• pp.2515-2517
• /
• 1999

In this paper we analysis DC bus voltage stress at high line voltage and light load in $S^4$-PFC Isolated AC/DC converter with DC bus voltage feedback using coupling in transformer. In this converter, the principle of operation and the practical problems in the design are considered. Simulation and experimental results are presented to verify the operation and performance of the $S^4$-PFC converter with DC bus voltage feedback. Experimental sets are performed in the conditions; switching frequency 100 kHz, output of 5 V, 60W, and universal line input voltage.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2003년도 추계학술대회 논문집
• /
• pp.267-270
• /
• 2003

In this paper, a new energy recovery circuit for AC PDP(Plasma Display Panel) is proposed to decrease a sustain voltage and voltage stress on switching elements. In the proposed circuit, two auxiliary capacitors are connected directly to the power source through switching elements and inductors when ground potential is supplied to the panel. Therefore, the voltage across auxiliary capacitors can be increased by turns over the half of the source voltage. Because the intrinsic capacitance of PDP is charged sufficiently from the auxiliary capacitors, the level of sustain voltage and the voltage stress on the switching devices are decreased. To verify the validity of the proposed energy recovery circuit, computer simulations using PSpice program are carried out.

• 한국초전도ㆍ저온공학회논문지
• /
• 제11권2호
• /
• pp.25-28
• /
• 2009

A 154kV class high-temperature superconducting (HTS) power cable system is developing in Korea. For insulation design of this cable, it is important that study on cryogenic electrical insulation design to develop the cold dielectric type HTS cable because the cable is operated under the high voltage environment in cryogenic temperature. Therefore, this paper describes a design method for the electrical insulation layer of the cold dielectric type HTS cable adopting the partial discharge-free design under ac stress, based on the experimental results such a ac breakdown strength, partial discharge inception stress, $V_{ac}$-t characteristics, $V_{imp}$-n characteristics, and impulse breakdown strength of liquid nitrogen/laminated polypropylene paper (LPP) composite insulation system in which the mini-model cable is immersed into pressurized liquid nitrogen.

• 한국전기전자재료학회논문지
• /
• 제24권12호
• /
• pp.939-943
• /
• 2011

In this paper, reliability of the two sandwiched MIM capacitors of $Al_2O_3-HfO_2-Al_2O_3$ (AHA) and $SiO_2-HfO_2-SiO_2$ (SHS) with hafnium-based dielectrics was analyzed using two kinds of voltage stress; DC and AC voltage stresses. Two MIM capacitors have high capacitance density (8.1 fF/${\mu}m^2$ and 5.2 fF/${\mu}m^2$) over the entire frequency range and low leakage current density of ~1 nA/$cm^2$ at room temperature and 1 V. The charge trapping in the dielectric shows that the relative variation of capacitance (${\Delta}C/C_0$) increases and the variation of voltage linearity (${\alpha}$/${\alpha}_0$) gradually decreases with stress-time under two types of voltage stress. It is also shown that DC voltage stress induced greater variation of capacitance density and voltage linearity than AC voltage stress.

• 한국식품과학회지
• /
• 제36권3호
• /
• pp.465-471
• /
• 2004

본 실험은 당뇨병 치료에 대한 연구로 우리나라에서 민간요법에 이용되어 오던 식물인 택사에서 혈당강하에 영향을 미친 butanol분획물과 항산화영양소인 비타민 E를 21일간 경구투여 하여 글리코겐, 지질함량 및 지질과산화에 미치는 영향을 검토하였다. 간, 신장 및 폐의 상대적 무게는 당뇨대조군이 정상군에 비해 유의적으로 높은 경향을 보였고 특히 신장은 현저한 비대현상을 나타냈다. 간장 글리코겐 함량은 당뇨대조군에 비해 Ac-VE투여군과 VE투여군에서, 근육의 글리코겐 함량은 VE투여군에서 유의적으로 증가하였다. 간장 콜레스테롤 함량은 당뇨대조군에 비해 Ac투여군과 VE투여군에서 감소하였다. 간장 중성지방 함량은 정상군에 비해 당뇨대조군에서 유의적으로 감소하였으며 당뇨대조군에 비해 모든 당뇨실험군에서 증가하였으며 VE투여군에서 유의적으로 증가하였다. 간장의 MDA 함량은 당뇨대조군에 비해 당뇨실험관에서 감소하였으며 Ac투여군과 Ac-VE투여군에서는 유의적으로 감소하였다. 폐의 경우는 당뇨대조군에 비해 모든 당뇨실험군에서 감소하였으나 유의적인 차이는 없었다. 이상의 결과 streptozotocin으로 당뇨를 유발시킨 흰쥐에서 택사의 투여가 간의 산화적 손상을 감소시키므로써 산화적 스트레스 억제효과를 관찰할 수 있었으며, 비타민 E의 투여가 간장 및 근육의 글리코겐 함량을 증가시키고 중성지방함량을 증가시켰다. 택사와 VE의 상관관계는 보이지 않았고 각자 독자적인 기전에 의해서 발생하는 것으로 사료된다. 그리므로 앞으로 각 조직의 지방대사 및 약물대사효소활성에 비치는 영향에 대해 더욱 연구되어져야 할 것이다.

• 전력전자학회논문지
• /
• 제14권6호
• /
• pp.449-456
• /
• 2009

본 논문에서는 PFC단 링크 캐패시터의 실효 전류를 크게 저감 할 수 있는 링크 캐패시터 전류 스트레스 저감기법을 제안한다. 링크 캐패시터 선정 기준에는 여러 가지가 있으나 가장 큰 비중을 차지하는 것이 캐패시터 실효전류이다. 제안된 C-L 필터는 PFC단 출력 전류를 필터링하여 링크 캐패시터의 실효 전류를 크게 줄일 수 있고, 제안된 C-L-L-C 필터는 C-L 필터의 출력 전류 필터링 효과와 함께 L-C 필터가 DC/DC단 입력 전류를 필터링 함으로써 링크 캐패시터의 실효 전류를 더욱 크게 줄일 수 있다. 제안된 필터는 설계가 간단하고 PFC단의 Crossover frequency가 매우 낮아 C-L 필터 및 C-L-L-C 필터의 Cut-off frequency가 PFC단의 제어기 루프에 영향을 주지 않으므로 적은 소자를 가지고 손쉬운 방법으로 링크 캐패시터의 실효전류를 크게 줄일 수 있다. 제안된 필터의 이론적 해석과 설계 방법을 제시하며, 실험을 통하여 그 우수성을 검증한다.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
• /
• pp.529-533
• /
• 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.

• 한국전기전자재료학회논문지
• /
• 제13권8호
• /
• pp.704-710
• /
• 2000

Metal electrode materials for plasma display panel should have low electrical resistivity in order to maintain stable gas discharge and have fast response time. They should also hae good film uniformity adhesion and thermal stability. In this study Cr/Cu/Cr metal electrode structure is formed by DC magnetron sputtering. Cr and Cu films were deposited on ITO coated glasses with various DC power density and main pressures as the major parameters. After metal electrodes were formed a heat treatment was followed at 55$0^{\circ}C$ for 20 min in a vacuum furnace. The intrinsic stress of the sputtered Cr film passed a tensile stress maximum decreased and then became compressive with further increasing DC power density. Also with increasing the main pressure stress turned from compression to tension. After heat the treatment the electrical resistivity of the sputtered Cu film of 2${\mu}{\textrm}{m}$ in thickness prepared at 1 motor with the applied power density of 3.70 W/cm$^2$was 2.68 $\mu$$\Omega$.cm With increasing the main pressure the DC magnetron sputtered Cu film became more open structure. The heat treatment decreased the surface roughness of the sputtered Cr/Cu/Cr metal electrodes.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 추계학술대회 논문집 전기물성,응용부문
• /
• pp.244-247
• /
• 2004

The electrical insulating design is important to realize a HTS power cable because the cable is operated under the high voltage environment. For the insulation design of a HTS power cable, it is necessary to investigate the AC, impulse breakdown and partial discharge(PD) inception stress of liquid nitrogen/LPP composite insulation system. Based on these results, the electrical insulation of a HTS power cable is designed and Mini-model cables are manufactured. The manufactured Mini-model cables are evaluated that AC, impulse withstand voltage, breakdown and partial discharge inception stress and analyzed characteristics insulation of HTS cable bending condition according to this paper. From these tests, the AC, impulse withstand voltage test and partial discharge inception stress is satisfied "standard technical specification of KEPCO" in Korea and the breakdown voltage was 120kV.