• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
• /
• pp.391-394
• /
• 2006

This paper presents soft switching zero voltage switching high frequency inverter for rare gas fluorescent lamp using dielectric-barrier discharge phenomenon. The simple high-frequency inverter can completely achieve stable zero voltage soft switching (ZVS) commutation for wide its output power regulation ranges and load variations under its constant high frequency pulse density modulation (PDM) scheme. Its transient and steady state operating principle is originally described and discussed for a constant high-frequency PDM control strategy under a stable ZVS operation commutation, together with its output effective power regulation characteristics-based on the high frequency PDM strategy. The experimental operating performances of this high frequency Inverter are illustrated as compared with computer simulation results and experimental ones. Its light dimming characteristics due to power regulation scheme are evaluated and discussed on the basis of simulation and experimental results. The feasible effectiveness of this high frequency inverter appliance implemented here is proven from the practical point of view.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• 제35권4호
• /
• pp.322-332
• /
• 2022

Energy storage capacitors based on dielectric ceramics with superior polarization properties and dielectric constant can provide much higher output power density due to their very fast energy charging/discharging rates, which are particularly suitable for operating pulsed-power devices. For an outstanding energy storage performance of dielectric capacitor, a large recoverable energy density could be derived by introducing a slim polarization-electric field hysteresis loop into dielectric materials by various technical approaches. Many research teams have explored various dielectric capacitor technologies to demonstrate high output power density and ultrafast charging/discharging behavior. This article reviews the recent research progress in high-performance dielectric capacitors for pulsed-power electronic applications.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• 제65권12호
• /
• pp.1992-1999
• /
• 2016

The plasma process is applied to various industrial fields such as high-tech IT industry, textiles and medical. Therefore, there is increasing interest in the plasma power supply, and demand for power devices of high efficiency and high power density is increased. Plasma power supply for process must solve the arc problem, when the plasma is unstable. The output capacitor is closely related to the arc problem. If the output capacitor is smaller, the damage from the arc problem is reduced. However, the small value of the output capacitor affects the operating characteristics of the power supply. In this paper, a LLC resonant converter is adopted, because it can achieve high efficiency and power density in the plasma DC power supply. However, due to the small value of the output capacitor, the converter is operated as a LLCC resonant converter. Therefore, a gain characteristic of LLCC resonant converter is analyzed by using the FHA (First Harmonic Approximation) in plasma power supply. Simulation and experimental results are presented to verify the characteristic analysis of LLCC Resonant Converter.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• 제43권11호
• /
• pp.98-104
• /
• 2006

The conventional burst-mode APC(Automatic Power Control) circuit had an effective structure that was suitable for a low power consumption and a monolithic chip. However, as data rate was increased, it caused errors due to the effect of the zero density. In this paper, we invented a new structured peak-comparator which could compensate the unbalance of the injected currents using double gated MOS and MOS diode. And we proposed a new burst-mode APC adopting it. The new peak-comparator in the proposed APC was very robust to zero density variations maintaining the correct decision point of the current comparison at high data rate. It was also suitable for a low power consumption and a monolithic chip due to lack of large capacitors.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• 제56권7호
• /
• pp.1250-1254
• /
• 2007

The multi-resonant(MR) converter has a characteristics that the parasitic components existing in the converter are absorbed into the resonant circuits. The designed MR converter could be got a high efficiency and a high power density because the switching power losses are reduced effectively due to resonant switching circuit. However, the high resonant voltage stress of switching power devices leads to the conduction loss. In this paper, it is proposed the novel alternated(AT) flyback multi-resonant converter to overcome such a drawback. The suggested converter dc input is divided by two series input filter capacitors. The resonant stress voltage is reduced to 2-3 times the input voltage without any complexity and it provides the various circuit schemes in lots of applications. The proposed flyback MR converter is verified through simulation and experiment.

• Journal of Power System Engineering
• /
• 제9권4호
• /
• pp.143-147
• /
• 2005

Graphites is well known to have superior advantages to high-temperature, high-pressured, and strong acid-state gas or liquid because it is very stable and chemical structure. Nowadays the new plant with high performance is developed in field of chemical industries, so the need of graphites is increasing rapidly. In this paper, newly developed graphite products with high density is investigated by the mechanical properties of that. I introduced the graphite material which developed for this experiment by the forming process in order to compare to the commercial graphite sheet from expanded graphite which made by the rolling process. Through measuring density and hardness test also tensile test, I investigated the characteristics of these materials. It is verified that the newly developed graphite products forming method is able to make graphite products which have superior mechanical properties than that of commercial graphite sheet.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• 제48권5호
• /
• pp.349-353
• /
• 1999

In this paper, to fabricate the AC power electroluminescent device (PELD) with high brightness, new structure that constructed single emissive layer between electrodes was proposed. Dielectric and phosphor material structure that constructed single emissive layer between electrodes was proposed. Dielectric and phosphor material were BaTiO3 and ZnS:Cu respectively. Fabricated AC power EL devices were estimated by optical and electrical properties of EL spectrum, brightness, CIE coordinate system, transferred charge density and EL emission wave in time domain. With above results, we found that brightness of newly proposed AC powder EL power EL device was 2754 cd/m2 at 100V, 400 Hz and compared with conventional device structure.

• The Transactions of the Korean Institute of Power Electronics
• /
• 제22권6호
• /
• pp.510-516
• /
• 2017

This paper proposes a single-stage interleaved totem-pole on-board battery charger with a simple structure and a reduced component count. Apart from achieving ZVS turn-on of all switches and ZCS turn-off of all diodes, this charger does not require an input filter due to its CCM operation and bulky electrolytic capacitors, which in turn result in a high power density. A single-stage power conversion technique is applied to the interleaved structure in order to achieve a high power density and high efficiency. A 2.5 kW prototype of the proposed charger is also built and tested to validate the proposed operation.

• Journal of the Korean Ceramic Society
• /
• 제56권1호
• /
• pp.1-23
• /
• 2019

Dielectric materials with inherently high power densities and fast discharge rates are particularly suitable for pulsed power capacitors. The ongoing multifaceted efforts on developing these capacitors are focused on improving their energy density and storage efficiency, as well as ensuring their reliable operation over long periods, including under harsh environments. This review article summarizes the studies that have been conducted to date on the development of high-performance dielectric ceramics for employment in pulsed power capacitors. The energy storage characteristics of various lead-based and lead-free ceramics belonging to linear and nonlinear dielectrics are discussed. Various strategies such as mechanical confinement, self-confinement, core-shell structuring, glass incorporation, chemical modifications, and special sintering routes have been adopted to tailor the electrical properties and energy storage performances of dielectric ceramics. In addition, this review article highlights the challenges and opportunities associated with the development of pulsed power capacitors.

• Proceedings of the Korean Vacuum Society Conference
• /
• 한국진공학회 2011년도 제40회 동계학술대회 초록집
• /
• pp.50-50
• /
• 2011

The aluminum nitride films were prepared by RF magnetron sputtering using an AlN ceramic target. The crystallinity, grain size, Al-N bonding and thermal conductivity were investigated in dependence on the plasma power densities (4.93, 7.40, 9.87 W/$cm^2$) during sputtering. High thermal conductivity is important properties of A1N passivation layer for functioning properly in thermal inkjet printhead. The crytallinity, grain size, Al-N bonding formation and chemical composition were observed using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS), respectively. The AlN thin film was changed from amorphous to crystalline as the power density was increased, and the largest grain size appeared at medium power density. The near stoichiometry Al-N bonding ratio was acquired at medium power density. So, we know that the AlN thin film had better thermal conductivity with crystalline phase and near stoichometry Al-N bonding ratio at 7.40 W/$cm^2$ power density.