• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2695-2697
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• 1999

A new three-phase voltage-fed inverter using partial resonant converter with high power factor and high efficiency is proposed. The proposed Flyback converter is constructed by using a resonant network in parallel with the switch of the conventional converter. The devices are switched zero voltage or zero current eliminating the switching loss. This paper introduces elimination of harmonics compared with conventional SPWM inverter and three-phase voltage-fed inverter using Flyback converter.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.328.2-328
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• 2002

General modeling of a resonant shunting damper has been made Iron piezoelectric sensor/actuator equation. It is found that an additional damping, which is augmented to a system, is generated by the shunt damping effect The transfer function of the tuned electrical absorber is derived for both series and parallel shunt circuit. The governing equations and associated boundary conditions are derived using Hamilton's Principle. The shunt voltage equation is also derived from the charge generated in PZT due to beam vibration. The frequency response function of the obtained mathematical model is compared with that of the tuned eledtrical absorber and experimental work. The vibration amplitude is reduced about 15 dB at targeted second mode frequency.

• Structural Engineering and Mechanics
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• v.61 no.4
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• pp.453-461
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• 2017

This paper presents the series multiple tuned mass dampers (STMDs) to suppress the resonant vibrations of railway bridges under the passage of high-speed trains (HSTs). A STMD device consisting of two spring-mass-damper units connected each other in series is installed on the bridge. In solution, bridge is modeled as a simply-supported Euler-Bernoulli beam with constant cross-section, and vehicle is simulated as a series of moving forces with constant speed. By the assumed mode method, the governing equations of motion of the beam-TMD device coupled system traversed by a moving train are obtained. The optimum values for the parameters of the STMD device are obtained for the criterion based on the minimization of the maximum dynamic displacement of the beam at its midspan. Single TMD and multiple TMDs in parallel are also considered for demonstration of the STMD device's performance. The results show that STMDs are effective in bridge vibration suppression and robust to parameters' change in the main system and the absorber itself.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.81-83
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• 2006

The conventional cold cathode fluorescent lamp (CCFL) driver for LCD TV has a transformer for each lamp to step up the high sinusoidal waveform from the low input voltage. The transformer used in the conventional topology causes the driver to have bulky size and high cost. This paper proposes a new transformer-less CCFL driver for LCD backlight that is based on the parallel-loaded resonant inverter topology. This resonant topology enables the circuit to supply enough high voltage for CCFL without a transformer. Also, with current-balancing technique, this transformer-less inverter drives 16 CCFL lamps.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2100-2102
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• 1998

A full bridge double resonant type inverter using Phasor shift suitable for heating magnetic and nonmagnetic at high frequency is described. A series-parallel arrangement of capacitor is adopted and optimum mode of operation is proposed. Also, Based on the characteristics value, a method of circuit design is proposed.

• Proceedings of the Korea Crystallographic Association Conference
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• 2002.11a
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• pp.36-36
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• 2002

To Establish of standard technique of length measurent in 2D plane, we develope AFM system. The XY scanner scans the sample only in XY plane, while the Z scanner scans the specimen only in Z-direction. Cantilever tip is controlled to has constant height relative to speciman surface by feedback of PSPD signal. To acquire high accuracy, Z-axis measuring sensor will be added.(COXI or others). In this paper we design XYZ stage suitable for this AEM system. For XY stage, single module parallel-kinnematic flexure stage is used which has high orthogonality and minimum out-of-plane motion. To obtain best performance optimal design is performed. For XY stage, to be robust about parasitic motion optimal design of maximizing Z and tilt stiffness is performed under the constraint of motion range and stage size. And for Z stage, optimal design of maximizing 1st resonant frequency is performed. Because if resonant frequency is get higher, scan speed is improved. So it makes reduce the error by sensor drift. Resultly XYZ stage each have 1st natural frequency of 115㎐, 201㎐, 2.66㎑ and range 109㎛, 110㎛, 12㎛.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.2
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• pp.91-98
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• 1998

The current-fed high frequency inverter with separated parallel resonant capacitor is presented in this paper. The analysis of the proposed circuit is generally described by using normalized parameter, and are evaluated characteristics of the circuit.In addition, this paper proves the propriety of theoretical analysis in terms of the experimental waveforms using the switching device MOSFET. In the future, the proposed inverter will expected that it can be practically used as the high frequency power source for induction heating etc.ng etc.

• Proceedings of the KIEE Conference
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• summer
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• pp.1211-1213
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• 2004

CCFL(cold cathode fluorescent lamp) are used to backlight of LCD(liquid crystal display). CCFL dimming methods are used to pulse frequency modulation(PFM) or pulse width modulation(PWM). In this paper, design of CCFL driving and control circuit by half-bridge type series and parallel resonant inverter that variable frequency modulation method to control the output voltage current. Inverter switching frequency is higher than resonant frequency for stable operating, and it is possible dimming control. On the basis of equivalent circuit, the validity of this study is confirmed by the comparison of simulation and experimental result.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.8
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• pp.455-460
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• 1999

A novel zero-voltage-transition (ZVT) PWM converter for switched reluctance motor (SRM) drives is proposed. A simple auxiliary circuit which consists of one active switch, one resonant inductor, and three diodes provides ZVS condition to all main switches and diodes allowing high frequency operation of the converter with high efficiency. The auxiliary circuit is placed in parallel with the main power flow path and thus it handles only a small fraction of the main power. So, the power rating of the auxiliary circuit can be very small (about 30% of main power). So, the auxiliary circuit can be realized with small power rating and low cost. Operation, features and characteristics of the proposed converter are illustrated and verified on a 1.5 kW, 50 kHz IGBT based (a MOSFET for the auxiliary with) experimental circuit.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.847-849
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• 1993

Two new schemes of three-phase rectifier using softing switching methods are introduced for the input power factor correction. These three-phase rectifiers are employed the zero voltage switching for the parallel resonant and zero current switching for the series resonant AC link type rectifiers. The dynamic modeling and discontinuous integral cycle mode control technique are also presented. With the proposed circuits and control technique, the high power factor can be obtained.