• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.904-905
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• 2008

In this paper, a novel 60kV, 300A, 3kHz pulsed power supply based on IGBT stacks is proposed. Proposed scheme consists of series connected 9 power stages to generate maximum 60kV output pulse and 15kW series resonant power inverter to charge DC capacitor voltage. Each power stages are configured as 8 series connected power cells and each power cell generates up to 830VDC, 300A pulses. Finally pulse output voltage is applied using total 72 series connected IGBTs. The synchronization of gating signal is important of series operation of IGBTs. For gating signal synchronization, full bridge inverter and pulse transformer generates on-off signals of IGBT gating and specially designed gate power circuit was used.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.2
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• pp.63-68
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• 2005

Total 12 units of high power klystron-modulator systems as microwave source are under operation for 2.5 GeV electron linear accelerator in Pohang Light Source (PLS) linac. The klystron-modulator system has an important role for the stable operation to improve an availability statistics of overall system performance of klystron-modulator system. RF power and beam power of klystron are precisely measured for the effective control of electron beam. A precise measurement and measurement equipment with good response characteristics are demanded for this. Input power of klystron is calculated from the applied voltage and the current on its cathode. Tiny measurement error severely effects RF output power value of klystron. Therefore, special care is needed to measure precise beam voltage. Capacitive voltage divider (CVD), which divides input voltage as capacitance ratio, is intended for the measurement of a beam voltage of 400 kV generated from the klystron-modulator system. Main parameter to determine standard capacitance in the high arm of CVD is dielectric constant of insulation oil. Therefore CVD should be designed to have a minimum capacitance variation due to voltage, frequency and temperature in the measurement range. This paper will be present and discuss the design concept and analysis of capacitive voltage divider for a pulsed high-voltage measurement, and the empirical relations between capacitance effects and oil temperature variation.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.370-373
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• 1997

In this paper, we compose of the stepdown chopper and the current source inverter. Because dc side current of the current source inverter pulse with twice frequency of utility, we control that modulation factor of chopper is pulsed twice frequency. Therefore if voltage across the dc reactor equal to zero, it tis decreased. And we control modulation factor of the chopper to operate at maximum power point around of solar cell.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.4
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• pp.510-516
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• 2013

This paper suggests a 3-phase series-resonant type high voltage capacitor charger for an EML pulsed power system. The operating principle on the charger is explained by an equivalent circuit. Additionally, we analyze the charging characteristic in one discontinuous conduction mode and three continuous conduction modes. The analysis shows that the resonant current per phase is two thirds of the 3-phase charger's average charging current and one third of the single-phase charger's average charging current with the same capacity. We suggest a design method of the 3-phase capacitor charger in each operational mode and present an example of 3.5 kW capacitor charger at ${\omega}_s=0.33{\omega}_r$. The 3.5 kW 3-phase capacitor charger prototype is assembled with a TI28335 controller and a 40 kJ, 7 kV capacitor. The design rules based on the analysis are verified by experiment.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.939-944
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• 2001

For the application of simultaneous $DeSO_{2}\;&\;DeNO_{x}$ equipment using non-thermal plasma process to the industrial and power plants, the many types of plasma device and process were studied. The e-beam and pulsed plasma corona discharge process are outstanding for the study to apply commercial large-scale plant from among these. In this paper, non-thermal plasma of technical trends and the characteristics of system developed by Doosan heavy industries & construction Co., Ltd. are explained. We have researched pulsed plasma corona discharge process since 1994. At the basis of reasonable results for the pilot plant, we constructed the demonstration plant at a domestic coal-fired power plant in 1999, as the previous step for commercial use. In near future, enough information about designs and costs of commercial-size system will be obtained.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.168-168
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• 2013

도전성 섬유(Conductive textile)는 섬유자체의 고유 특성을 유지하면서 전기적인 도전 특성을 갖는 섬유로서, Cu, Ag, Ni 등의 전기전도성이 높은 금속 박막을 증착하여 제작하고 있다. 그러나, 이러한 금속은 공기 중의 산소와 결합하여 쉽게 산화되는 특성을 지니고 있기 때문에 사용 중에 산화되어 도전 특성이 감소하는 단점이 있다. TiN은 금속 못지않은 높은 전기전도성을 지니고 있을 뿐만 아니라, 금속에 비하여 높은 경도에 따른 우수한 내마모 특성, 내부식성 및 낮은 마찰계수를 지니고 있다. 그러나, TiN은 경도가 높기 때문에 섬유의 고유 특성인 유연성이 저하되는 문제가 있다. 본 연구에서는 면(Cotton), PE (Polyester), PP (Polypropylene) 등의 섬유 위에 TiN 박막을 증착하여, 섬유의 유연성을 유지하며 전기전도성과 내마모 특성이 우수한 도전성 섬유를 제작하고자 하였다. TiN 박막 증착을 위하여 ICP-assisted pulsed-DC reactive magnetron sputtering 장비를 사용하였으며, Ar:N2 유량비(Flow rate), Ti 타겟 power, ICP RF power 등을 변화시켜 Ti와 N의 조성비를 조절하였고, 이를 통하여 섬유의 휨이나 접힘에도 도전 특성이 변하지 않고 내마모 특성이 우수한 TiN 박막을 증착하였다. TiN 박막이 증착된 섬유의 전기전도도는 일정한 압력 하에 전기전도도를 측정할 수 있는 장치를 제작하여 측정하였으며, 표면 조성 분포 및 접합력 측정을 위하여 XPS (X-ray Photoelectron Spectroscopy)와 Peel-tester를 이용하였다.

• Journal of Adhesion and Interface
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• v.10 no.1
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• pp.17-22
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• 2009

Polymer thin films were prepared by radio frequency (RF) plasma polymerization of phthalic anhydride (PA). First, monomer vaporization temperature ($100{\sim}160^{\circ}C$) was optimized by evaluating the thermal properties of thin films using differential scanning calorimeter (DSC) and measuring the root-mean-square (RMS) roughness with atomic force microscope (AFM) at the fixed plasma power of 10 W and time of 5 min in a continuous-wave (CW) mode. Plasma power (5~20 W) was then optimized by measuring the film solubility in solvents such as toluene, acetone, dimethylsulfoxide (DMSO) and 1 methylpyrrolidine (NMP). Next, pulsed mode plasma polymerization was also studied by varying the duty cycle of on-time (5, 20%) under optimized conditions of continuous-wave (CW) mode ($120^{\circ}C$, 10 W) in order to increase the anhydride functional groups. Finally, polymer thin films were characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analyzer (TGA) and ${\alpha}$-step.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1600-1602
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• 2001

A pulsed power supply of 2.4MJ capacitor bank has been developed to make investigation into electric gun technology. It is made up of eight paralleled 300kJ modules, and can supply various shape of high current pulse by changing charging voltage, inductance, capacitance, and firing time of each module. The 300kJ module has been designed and fabricated for the maximum operating voltage of 22kV, peak current of 150kA, and pulse duration of 1msec. The experiments of the modules were done, and the equivalent circuit of the module was determined. The characteristics of the module were analyzed more deeply through the circuit simulation. The experiments of the paralleled modules with inductance of 20 $\mu$H and load resistance of 100 m$\Omega$ were performed, where the modules were discharged simultaneously and/or sequentially. The results of the experiments were analyzed. The 2.4MJ capacitor bank is currently used as the pulsed power supply for the ETCG (Electro Thermal Chemical Gun) research.

• Journal of Magnetics
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• v.20 no.4
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• pp.394-399
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• 2015

Electromagnetic Induction Launchers (EIL) have been receiving great attention due to their advantages of non-contact between the coils and a projectile. This paper describes the modeling and design of 3-stage EIL to accelerate a copper projectile of 50 kg with 290 mm diameter. Our EIL consists of three independent driving coils and pulsed power modules to generate separate driving currents. To find efficient acceleration conditions, the appropriate shape of the driving coils and the position of the projectile have been calculated by using a finite element analysis (FEA) method. The results showed that the projectile can be accelerated more effectively as the gap between the coils is smaller; a final velocity of 45 m/s was obtained. The acceleration efficiency was estimated to be 23.4% when a total electrical energy of 216 kJ was discharged.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.1
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• pp.24-29
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• 2004

$CF_4$ gas is one of the most useful gases in modern technologies for semiconductor fabrication. However, there are many problems which should be solved in order to fabricate semiconductor device, for example, etching speed drop due to ion charge-up and etching selectivity drop due to the high electron energy. One of useful method in order to suppress their damages above is pulsed-time modulated plasma (PM). However, transient responses of charged particles occur when the source power is turned-on and -off in PM method. To control plasma properties in detail, such a transient phenomenon must be investigated. In this paper, we investigate $CF_4$ RF plasma properties under a one-dimensional fluid model. And also for dynamic and stable control of $CF_4$ plasmas, we investigated the transient behavior of the plasmas after step up or down of the amplitude of the power source voltage $V_s$(t). Fundamental properties of transient $CF_4$ plasmas was discussed. Furthermore, we intend to discuss new method for pulsed-time plasma modulation.