• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 추계학술대회 논문집
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• pp.186-187
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• 2013

The paper presents a long-pulse modulator for klystron using a high-voltage solid-state switch and a droop compensator. The modulator guarantees the safe of klystron by limiting the amount of energy transferred to klystron in case of arc. The high performance of the modulator is also achieved by the fast transition time, high flatness and average power. The proposed prototype has produced pulses with a flat-top voltage -90[kV], pulse width 1ms and pulse frequency 200[Hz]. The validity of the long-pulse modulator for klystron has been verified by the simulation and experimental works.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.95-98
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• 2006

This paper proposes high speed SRM drive system for blower with a new 4-level inverter and precise excitation position generator. For the high speed blower, a proper inverter and control method are proposed and the output characteristics are analyzed. In order to get a fast build-up and demagnetization of excitation a current, 4-level inverter system is proposed. The proposed 4-level inverter has additional charge capacitor, power switch and diode in the conventional asymmetric converter. The charged high voltage is supplied to the phase winding for fast current build-up, and demagnetization current is charged to additional capacitor of 4-level inverter. In addition, a precise excitation position generator can reduce turn-on and turn-off angle error according to sampling period of digital control system. The proposed high speed SRM drive system is verified by computer simulation and experimental result.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.91-94
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• 2006

Miniature BLDC is widely used in industrial applications and especially medical appliances because of there character that high driving efficiency and high torque characteristic. However torque ripple of a high speed miniature BLDC is serous in switching period cue to the very electrical time constant. This paper present instant voltage and current control for torque ripple reduction of a high speed miniature BLDC. Computer simulation and experiment test for 40,000 rpm miniature BLDC show the verification of the proposed control method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.453-457
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• 1996

DC/DC converter is widely used in computer, electronic communication and industrial apparatus where the regulated dc supply is needed. FB-ZVS converter is suitable for high-power, high-frequency and constant frequency control. Because the voltage stress of the diode rectifier is high due to the ring effect, the clamp circuit is essential to reduce the voltage stress. The nondissipative active clamp circuit eliminates ring effect. Analysis of FB-ZVS converter and the validity of the active clamp circuit are studied through the simulation, and the experimental results show the superior characterics of the proposed system.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1997년도 전력전자학술대회 논문집
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• pp.393-399
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• 1997

Single-phase and three-phase AC to DC power converters are becoming frequently used for high voltage/high power applications such as telecommunications. They often require input/output transformer isolation for safety, a unity input power factor for minimum reactive power, free input harmonic currents fed back to the AC Power distribution system and, finally, high efficiency and high power density for minimum weight and volume. The proposed boost converter for power factor correction (PFC) provides an unity input power factor, low harmonic distortion and high efficiency along with reduced volume and weight. Single-phase 220VAC input/380VDC 1KW output prototype is constructed and experimental results will be verified with those of PSpice simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.537-540
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• 1991

This paper discusses with a voltage - fed Type high frequency inverter with simple main circuit and high efficiency. The proposed inverter is proper as a high frequency inverter of home applications applied with induction healing principle of high frequency. Further, its operating characteristics necessary to its design is estimated by analysis of a lumped circuit of heating system as a model.

• 조명전기설비학회논문지
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• 제27권6호
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• pp.68-74
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• 2013

Induction-heated system is innovative system which applied IH(Induction Heating) magnetic induction heating generated from induction-heated metallic package and high-frequency power circuit technique for thermal converse technique. In this occurs not burning, so that the working environment and deterioration of products can be improved. This technique is used high frequency inverter. By using high frequency inverter high frequency in the range of kHz can be made with conventional alternative current. In this contribution IGBT module is used for high frequency inverter. In this paper are discussed analysis of characteristics according to the each frequency and produced Flat plate induction heating system using 1.5kW-class half-bridge resonant inverter. In addition, operating characteristics of the system to changes in the distance between the coil and the heater, applications of system are also discussed.

• Journal of Microbiology and Biotechnology
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• 제11권2호
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• pp.204-210
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• 2001

Paclitaxel can be produced in high yield and with a high degree of purify from plant cell cultures of Taxus chinensis. The complete purification method was systematically established and described. This method was an efficient procedure for the purification of paclitaxel from crude paclitaxel, consisting or reverse-phase chromatography, followed by a normal-phase chromatography. The two-stage HPLC purification scheme serves as an effective and economical approach for resolving paclitaxel from complex mixtures of taxoids, with high purify (>99%) and low impurities (<0.1%). The process is readily scalable to a pilot plant and eventually to a production environment where multikilogram quantities of material are expected to be produced. The process has been optimized to minimize solvent usage, complexity, and operating costs.

• Interaction and multiscale mechanics
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• 제1권4호
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• pp.437-448
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• 2008

This paper examined the stability of high-dense dislocation substructures (HDDSs) associated with martensite laths in High Cr steels supposed to be used for FBR, based on a series of dislocation dynamics (DD) simulations. The DD simulations considered interactions of dislocations with impurity atoms and precipitates which substantially stabilize the structure. For simulating the dissociation processes, a point defect model is developed and implemented into a discrete DD code. Wall structure composed of high dense dislocations with and without small precipitates were artificially constructed in a simulation cell, and the stability/instability conditions of the walls were systematically investigated in the light of experimentally observed coarsening behavior of the precipitates, i.e., stress dependency of the coarsening rate and the effect of external stress. The effect of stress-dependent coarsening of the precipitates together with application of external stress on the subsequent behavior of initially stabilized dislocation structures was examined.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
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• pp.959-961
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• 1998

In this paper, we present design rule of high-voltage rectangular generator working in wide band frequency domain. Though power electronics now have voltage ratings up to several kV, it is difficult to design and fabricate high-voltage systems with the power electronic devices alone. So we have combined IGBT with technically designed transformer to get the high-voltage rectangular waveforms. In this work, next two things are the main factors. The first one is design of transformer working low-frequency domain of less than 10Hz. And the second one is adding offset voltage part. As a result, we can get variable frequency high-voltage rectangular waveform and this can be used as a voltage source of sandpaper manufacturing process.