• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.45-47
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• 2018

This paper describes the 40kV solid state pulsed power supply for environmental applications. The output specifications of the pulsed power supply are 40kV, 300A, 3kHz, and average output power of 13kW. In order to generate a high voltage, a series stacking cell structure is used which is charged in parallel and discharged in series. Due to this structure, there is no dynamic voltage balancing problem as well as static voltage balancing problem for switches used in high voltage pulse power supplies. To verify this pulse power supply design, PSpice modeling was performed. Finally, experimental results with non-inductive resistive load and gas treatment reactor proved the reliability of the solid state pulsed power supply.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1910-1912
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• 1996

This paper presents the results of laboratory experimentals to remove $SO_2$ and $NO_x$ by a pulsed corona discharge in the wire-plate reactor. A rotating spark gap switch was used to generate the pulse by chewing the dc high voltage. Repetition frequency of the pulse was 60Hz and rising time of 50ns. The photo pictures of positive streamer corona taken by ICCD camera, pulse voltage and current were measured using a digital oscilloscope. Simultaneous effects of $C_{2}H_{4}$ injection and heterogeneous chemical reactions on nonthermal plasma process to remove $SO_2$ and $NO_x$ from flue gas were investigated in the present study

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.1
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• pp.25-31
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• 2021

This paper describes the design of a power cell-based pulsed power modulator with fast rise times. The pulse-generating section of the pulse power modulator is a series stack of power cells. Each power cell is composed of a storage capacitor, a pulse switch, and a bypass diode. When the pulse switches are turned on, the capacitors are connected in series and the sum of voltages is applied to the load. For output pulses with fast rise times, an IGBT with fast turn-on characteristics is adopted as a pulse switch and the optimized gate driving method is used. Pspice simulation is performed to account for the gate driving method. A 10 kV, 12-power cell-based pulsed power modulator is tested under resistive load and plasma reactor load. The rise times of output pulses less than 20 ns are confirmed, showing that the pulsed power modulator can be effectively applied to pulsed power applications with fast rise times.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.417-418
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• 2001

석탄의 연소과정에서 필연적으로 발생하는 황(SOx) 및 질소산화물(NOx)을 제거하기 위한 방법중 하나인 동시처리기술중 PCD(pulsed corona discharge) 반응기의 반응조건은 첨가제의 성분 및 성상에 따라 다양하게 바뀌며 황 및 질소 산화물 제거반응에 큰 영향을 미친다(Akira M., 1995). 따라서 PCD 반응기에 유입되는 가스는 발전소 배기가스 조건을 적용한 상태에서 주입하는 첨가제의 종류 및 양을 변화시켜, 각종 첨가제의 주입이 탈황, 탈질 반응에 미치는 상승효과를 조사하였고 PCD 반응기에서 첨가제의 반응 현상을 규명코자 하였다(송영훈, 1997). (중략)

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2251-2252
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• 1999

In this paper, the effect of magnetic field was measured on NOx removal characteristics for wire-plate plasma reactor with magnetic field applied to electric field vertically. NOx from simulated diesel engine flue gas are decomposed by the corona discharge of DC, AC and Pulsed voltages in wire-plate reactor. Consumption power increased with increasing discharge voltage. When magnetic field was applied to electric field vertically, consumption power decreased. NOx removal rate and arc transition voltage of plasma reactor with magnetic field were higher than those of plasma reactor without magnetic field.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05b
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• pp.104-108
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• 2004

The effect of magnetic field was measured on NOx removal for cylinder-wire plasma reactor with magnetic field applied to electric field vertically. Power was supplied to plasma reactor using rotating spark gap switch. Consumption power increased with increasing discharge voltage. When magnetic field was applied to electric field vertically, consumption power was less than that without magnetic field because of lorenz's force. NOx removal rate of plasma reactor with magnetic field were higher, 10-15%, than that of plsama reactor without magnetic field. And NOx removal rate decreased with increasing gas flow rate.

• Journal of Industrial Technology
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• v.26 no.B
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• pp.173-181
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• 2006

We analyzed systematically particle growth in the pulsed $SiH_4$ plasmas by a numerical method and investigated the effects of pulse modulations (pulse frequencies, duty ratios) on the particle growth. We considered effects of particle charging on the particle growth by coagulation during plasma-on. During plasma-on ($t_{on}$), the particle size distribution in plasma reactor becomes bimodal (small sized and large sized particles groups). During plasma-off ($t_{off}$), there is a single mode of large sized particles which is widely dispersed in the particle size distribution. During plasma on, the large sized particles grows more quickly by fast coagulation between small and large sized particles than during plasma-off. As the pulse frequency decreases, or as the duty ratio increases, $t_{on}$ increases and the large sized particles grow faster. On the basis of these results, the pulsed plasma process can be a good method to suppress efficiently the generation and growth of particles in $SiH_4$ PCVD process. This systematical analysis can be applied to design a pulsed plasma process for the preparation of high quality thin films.

• Journal of Industrial Technology
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• v.21 no.B
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• pp.155-161
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• 2001

In this study, we analyzed the $NO_X$ removal efficiency and particle size distribution by the pulsed corona discharge process and investigated the effect of several process variables. The NO removal efficiencies and the particle characteristics were measured and analyzed as the function of initial concentrations of NO, $H_2O$, and $NH_3$, applied voltage, pulse frequency and residence time. As the frequency of applied voltage increases, or as the applied voltage increases or as the residence time increases, the NO removal efficiency increases. The change of initial $NH_3$ and $H_2O$ concentrations do not affect the NO removal efficiency significantly. The particle concentration and size increases with the increases of initial NO concentration, residence time and applied voltage.

• Nuclear Engineering and Technology
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• v.48 no.3
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• pp.711-718
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• 2016

Steady-state operation of a fusion power plant requires external current drive to minimize the power requirements, and a high fraction of bootstrap current is required. One of the external sources for current drive is lower hybrid current drive, which has been widely applied in many tokamaks. Here, using lower hybrid simulation code, we calculate electron distribution function, electron currents and phase velocity changes for two options of demonstration reactor at the launched lower hybrid wave frequency 5 GHz. Two plasma scenarios pertaining to two different demonstration reactor options, known as pulsed (Option 1) and steady-state (Option 2) models, have been analyzed. We perceive that electron currents have major peaks near the edge of plasma for both options but with higher efficiency for Option 1, although we have access to wider, more peripheral regions for Option 2. Regarding the electron distribution function, major perturbations are at positive velocities for both options for flux surface 16 and at negative velocities for both options for flux surface 64.

• 한국연소학회:학술대회논문집
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• 1999.10a
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• pp.117-128
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• 1999

The removal of nitrogen oxides(NOx) from $N_{2}/O_{2}$ gas using a pulsed corona discharge was investigated as a function of the reduced electric field(E/N) and the energy density(J/L). A kinetic model was developed to characterize the chemical reactions taking place in a pulsed corona discharge reactor. The model calculates the fractional concentrations of radical species at each pulse-on period and utilizes the radicals to remove NOx for the subsequent pulse-off period. Electron collision reaction data are calculated using ELENDIF program to solve Boltzmann equation for electron energy distribution function, and the subsequent chemical reactions are calculated using CHEMKIN-II program to solve stiff ODE(ordinary differential equation) problems for species concentrations. The corona discharge energy per pulse and the time-space averaged E/N were obtained by fitting the model to experimental data. The model calculation shows good agreement with the experimental data, and predicts the formation of other species such as $NO_{2}$, $O_{3}$ and $N_{2}O$.