• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.4
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• pp.74-80
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• 2003

Ionic wind is produced by a corona discharge when a DC high voltage is applied across the point-to-plane gap geometry. The corona discharge phenomena have been investigated in several beneficial application fields such as electrostatic cooling, ozone generation, electrostatic precipitation and electrostatic spraying. Recently ionic wind might be used in aerodynamic, for example, heat transfer, airflow modification, and etc. In this work, in order to analyze the control behavior of the velocity and amount of ionic wind produced by the positive DC corona discharges. The ionic wind velocity was measured as a function of the applied voltage, diameter of the punched hole on plate electrode and separation between the point-to-plate electrodes. As a results, the airflow is generated from the tip of needle to the plate electrode in the needle-to-punched-plate electrode systems. The ionic wind velocity is linearly increased with an increase in applied voltage and ranges from 1 to 3 m/sec at the locations of 100-200 mm from the punched-plate.

• Applied Science and Convergence Technology
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• v.26 no.5
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• pp.118-128
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• 2017

The scope of this work is to determine and compare the effect of electron temperature ($T_e$) and number density ($N_e$) on the yield rate and concentration of reactive chemical species ($^{\bullet}OH$, $H_2O_2$ and $O_3$) in an argon, air and oxygen injected negative DC (0-4 kV) capillary discharge with water flow(0.1 L/min). The discharge was created between tungsten pin-to pin electrodes (${\Phi}=0.5mm$) separated by a variable distance (1-2 mm) in a quartz capillary tube (2 mm inner diameter, 4 mm outer diameter), with various gas injection rates (100-800 sccm). Optical emission spectroscopy (OES) of the hydrogen Balmer lines was carried out to investigate the line shapes and intensities as functions of the discharge parameters such as the type of gas, gas injection rate and inter electrode gap distances. The intensity ratio method was used to calculate $T_e$ and Stark broadening of Balmer ${\beta}$ lines was adopted to determine $N_e$. The effects of $T_e$ and $N_e$ on the reactive chemical species formation were evaluated and presented. The enhancement in yield rate of reactive chemical species was revealed at the higher electron temperature, higher gas injection rates, higher discharge power and larger inter-electrode gap. The discharge with oxygen injection was the most effective one for increasing the reactive chemical species concentration. The formation of reactive chemical species was shown more directly related to $T_e$ than $N_e$ in a flowing water gas injected negative DC capillary discharge.

• Journal of the Korean Society of Safety
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• v.29 no.6
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• pp.46-48
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• 2014

This paper compared and demonstrated the performance of the earth plate for conventional type and early streamer discharging type developed a new plate in order to improve the performance of the ground plate for use in grounding. The results obtained are shown below; early streamer discharge earth plate was high 5 kV on DC flashover voltage and corona discharge current was higher than about 2 times under the same test conditions compared to the conventional earth plate. From the experiential result, streamer discharge earth plate had a function of rapid inflow/out flow than the general ground plane because of by corona discharge current to be generated in the sharp serrated in formed the ground plane when strike current occurred. In the future, the newly developed early streamer discharge ground plate would be beneficial for grounding work to be widely used to promote the convenience and economy of construction.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.30 no.1
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• pp.66-71
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• 2016

In this study, electrical and spectroscopic characteristics were investigated in the pin to plate discharge of 0.9% weight per unit volume saline solution. The positive and positive- and negative-going dc pulse with 5% duty ratio were applied to tungsten pin electrode. The more amount of discharge current flew in negative discharge. The temperature, which is considered as a local value in the vicinity of vapor of discharge, was about 3,000K which is much higher than the value recommended to be controlled. It can be suggested that not only the temperature of liquid but also the local temperature of vapor is monitored to investigate damages on tissue or cells in biological application.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.754-760
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• 2011

In the DC traction system, a large load current of electric railcar leads to a voltage drop when a vehicle starts, and the regenerative power generated by brake system increases the catenary voltage. To minimize the voltage fluctuation during the train operation and make use of the regenerative power, several types of energy storage systems are being studied. The energy storage system that is being recently introduced consists of the supercapacitors for energy storage and the bi-direction DC/DC converter for charge/discharge control. The efficiency of the energy storage system depends on the train operation pattern. In this paper, the operation efficiency of the energy storage system was quantitatively analyzed via simulation study taking consideration of the train operation patterns. The simulation was conducted changing the headway of trains with the energy storage system that uses the bi-direction DC/DC converter and supercapacitor. The simulation results showed that the operation efficiency of the energy storage system increases as the headway increase.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.35-36
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• 2013

본 논문은 EV(Electric Vehicle)에 사용되는 배터리의 충/방전 전류에 따른 SOC(State of Charge) 및 전압특성을 Matlab Simulink로 구현하였으며, 검증을 위해 양방향 DC-DC 컨버터를 설계하여 실험을 하였다. 배터리 모델에 사용된 파라미터는 Randles등가회로를 기반으로 펄스방전을 통해 추출하였고, 단자전압 계산부에 3D Look-up 테이블을 이용해 적용하였다. SOC계산부는 전류에 따른 용량변화를 보상하기 위해 Peukert Effect를 적용하였으며, FTP-75 전류패턴으로 온도($0^{\circ}C$, $25^{\circ}C$, $40^{\circ}C$)에 따라 실험한 결과 시뮬레이션의 오차율은 5%로 높은 정확도를 갖는 것을 확인을 통해 검증 하였다.

• Proceedings of the KIPE Conference
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• 2007.11a
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• pp.21-23
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• 2007

In this paper a high efficiency bi-directional DC-DC converter for hybrid vehicles is proposed. The proposed converter a three-phase half-bridge interleaved ZVS converter, is designed to have high efficiency in the main operation range. The component ratings are calculated, the actual devices are selected, and the efficiency analysis has been performed to determine optimal ZVS range. The input and output current ripples are significantly reduced due to the interleaved operation. The dual loop control for the interleaved three-phase converter is also presented. To confirm the proposed convert ter, The simulation and experimental results are presented.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.23-24
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• 2014

본 논문은 절연형 양방향 DC-DC 컨버터의 방전모드와 변압기 권선비에 따른 손실 분석에 대해 다루었다. Phase-Shift방전모드와 Boost방전모드에서 변압기 권선비에 따른 스위치손실을 분석하여 손실을 최소로 하는 변압기 권선비와 최적의 방전모드를 결정하고자 한다.

• Journal of the Korea Society of Computer and Information
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• v.23 no.12
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• pp.179-184
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• 2018

In this paper, we have proposed the development of DC-DC converter for LRT power supply. First of all, we have studied converter technology, main functions and characteristics were determined. In also, the converter design was carried out to meet the system design conditions. Based on this design, converter simulation is performed to enable stable charging and discharging of the vehicle system. We have performed the Light-load test according to charge mode, discharge mode. As a result, the manufactured converter performance was verified through the load test, and it's stability was confirmed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.589-592
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• 2011

In this paper, bidirectional DC-DC converter is designed to cover up defects of fuel cell generating system like as low dynamic characteristic, unstable output and lack of storage ability by using bidirectional DC-DC Converter and supercapacitor that available to charge & discharge quickly, high efficient at charge & discharge and semi-permanent. Operating efficiency has been analyzed through simulation and examination. According to these design and data, hybrid system has been made and operation test, evaluation and results evaluation have been performed.