• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1416-1417
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• 2007

The high frequency pulsed power system is widely available for use in high frequency generator applications. We designed and fabricated our own high frequency pulsed power system to obtain very sort pulse width and high peak value and investigated microbe removal characteristics using it. This paper introduces a simple high voltage high frequency pulsed power system for removing various bacteria caused by dirty water. This system include power supply circuit, switching MOSFET, and flyback converter. We can also control the switching using a PIC one chip microprocessor. As a result, we can obtain good removing characteristics of various bacteria by adjusting the charging voltage, the pulse repetition rate and the electrical field inducing time.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.480-482
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• 1999

TCN standard has been applied to international train for provision of interoperability among European countries. In this paper, several TCN analyzers developed by European companies are introduced and the urgent need of TCN project engineering tool is emphasized for Korean High Speed Train.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.189-197
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• 2017

This paper elaborates two novel proposed topologies (type-I and type-II) of the high step-up DC-DC converter using switched inductor and voltage multiplier cell. The advantages of these proposed topologies are the less voltage stress on semiconductor devices, low device count, high power conversion efficiency, high switch utilization factor and high diode utilization factor. We analyze the Type-II topologies operating principle and mathematical analysis in detail in continuous conduction mode. High-intensity discharge lamp for the automotive application can use the derived topologies. The proposed converters give better performance when compared to the existing types. Also, it is found that the proposed type-II converter has relatively higher voltage gain compared to the type-I converter. A 40 W, 12 V input voltage and 72 V output voltage has developed for the type-II converter and the performances are validated.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.291-293
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• 2003

A semiconductor switch-based fast hi-polar high voltage pulse generator is proposed in this paper The proposed pulse system is made of a thyristor based-rectifier, DC link capacitor, a push-pull resonant inverter, a high voltage transformer. secondary capacitor, a high voltage IGBT & diode stacks, and a variable capacitor. The proposed system makes hi-polar high voltage sinusoidal waveform using resonance between leakage inductance of the transformer and secondary capacitor and transfers energy to output load at maximum of the secondary capacitor voltage. Compared to previous hi-polar high voltage pulse power supply using nonlinear transmission line, the proposed pulse power system using only semiconductor switches has simple structure and gives high efficiency

• Journal of the Korean Society for Precision Engineering
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• v.19 no.7
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• pp.88-96
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• 2002

High-speed machining is one of the most effective technologies to improve productivity. Because of the high speed and high feed rate, high-speed machining can give great advantages for the machining of dies and molds. This paper describes on the improvement of machining accuracy in high-speed machining. Depth of cut, feed rate and spindle revolution are control factors. The effect of the control factors on machining accuracy is investigated using two-way factorial design.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.11
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• pp.1622-1625
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• 2014

The main measurement uncertainty factors in DC high-voltage dividers for a national high-voltage standard are the measurement uncertainty of low-voltage arm and the stability of a high-voltage supply. In this study, the uncertainties by the two factors are greatly improved. As a result the measurement uncertainty for the DC high-voltage divider is reduced from $16{\times}10^{-6}(k=2)$ to $8{\times}10^{-6}(k=2)$ which is at international level.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.1
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• pp.51-58
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• 2015

In order to decrease the size of a switch mode power supply, high switching frequency can be an efficient way to reduce the size of passive components in the converter. In this paper, a 500-kHz high-frequency LLC resonant converter is proposed with an accurate design method of magnetizing inductance, as well as the relationship between the switching frequency and the size of the passive components. Simulation and experimental results are presented to verify the proposed methods and equations, including the temperature data of each passive and active device of the converter. Using those results, dominant power losses in the prototype converter under 500-kHz high-frequency operation are investigated, compared with the results from a 100-kHz converter. In addition, operating waveforms and power conversion efficiency will be shown to obtain design considerations for the high switching frequency LLC resonant converter.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1426-1428
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• 2000

A new block system - MAS (Moving Autoblock System) whose efficiency is higher than FAS(Fixed Autoblock System) in the loading capacity is required to accomodate the increasing transport volume. That MAS has higher efficiency has already been verified through various studies, especially in a line with different types of travelling trains. The efficiency of MAS for Korean high speed line with two different train model is analyzed by computer simulation. The results show that MAS is more efficient than FAS in the loading capacity.

• Journal of Power Electronics
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• v.8 no.1
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• pp.60-73
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• 2008

In this paper a three-phase ac-to-dc resonant converter with high input power factor and isolated output is proposed. To improve the input power factor of the converter, high frequency current is injected into the input of the three-phase diode bridge rectifier. It is injected through an impedance network consisting of a series of L-C branches from the output of the high frequency three-phase inverter. A narrow switching frequency variation is required to regulate the output voltage. A design example with different design curves is illustrated along with the component ratings. Experimental verification of the converter is performed on a prototype of 3 kW, 1000 V output, operating above 300 kHz. Experimental results confirm the concept of the proposed converter. Narrow switching frequency variation is required to regulate the output voltage.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1305_1306
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• 2009

Recently, piezoelectric transformer is applied to wide fields. Multi layer piezoelectric transformer has the advantage of high step up ratio, high electromechanical coupling coefficient(Kp) and high mechanical quality factor(Qm), however it shows the peeling-phenomenon of electrode, and high price due to high sintering temperature. Therefore this study focus on the method for fabrication of high power rosen type piezoelectric transformers.