• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.747-749
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• 2003

When the input current wave forms of Linear Pulse Motor(LPM) is excited as three difference type such as the square, the rectangular and the micro sinusoidal wave, this paper is proposed the calculation of thrust on the base of magnetic equivalent circuit of LPM. The thrust is analyzed and compared by the analytical method, the F.E.M. and the experimental values. Also, to decide the input current wave for optimal operation condition, the vibration of LPM is experimented and estimated.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.682-683
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• 2006

Thermoelectric conversion efficiency of thermoelectric elements can be increased by using a structure combining n-type and p-type semiconductors. From the above point of view, attention was directed at ZnO as a candidate n-type semiconductor material and investigations were made. As the result, a dimensionless figure of merit ZT close to 0.28 (1073K) was obtained for specimens produced by the PCS (Pulse Current Sintering) method with addition of specified quantities of $TiO_2$, CoO, and $Al_2O_3$ to ZnO. It was found that the interstitial $TiO_2$ in the ZnO restrains the grain growth and CoO acts onto the bond between grains. The influence of the inclusion of $TiO_2$ and CoO onto the sintering behavior also was investigated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.186-187
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• 2007

In this work, a temperature stable PWM(Pulse width modulation) circuit is proposed. The designed PWM circuit has a temperature dependent current source and a temperature independent voltage to compensate electrical characteristics with operating temperature. The variation of driving current is from about 4% to -6% in the temperature range $0^{\circ}C\;to\;70^{\circ}C$ compared to the current at the room temperature. The variation of bandgap voltage reference is from about 1.3% to -0.2% with temperature when the supply voltage is 3.3 volts. From simulation results, the variation of output pulse width is less than from 0.86% to -0.38% in the temperature range $0^{\circ}C\;to\;70^{\circ}C$.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.685-692
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• 2011

DC/DC switching power converters produce DC output voltages from different DC input sources. The converters can be used in regenerative braking of DC motors to return energy back in the supply, resulting in energy savings for the systems containing frequent stops. The current mode DC/DC converter is composed of a PWM (pulse width modulation) controller, a MOSFET, and inductor, etc. Pulse width modulation is applied to control and regulate the total output voltage. It is shown that the variation of threshold voltage at MOSFET and the offset voltage increase caused by radiation effects make the PWM pulse unstable. In the PWM operation, the missing pulses, the changes in pulse width, and a change in the period of the output waveform are studied by simulation program with integrated circuit emphasis (SPICE) and experiments.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.5
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• pp.413-422
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• 1999

Auto-connected multipulse(12/24pulse) rectifier schemes are cost effective methods for reducing line current hamonics in PWM drive systems. Employing these schemes to enhance utility power quality requires careful attention to several design considerations In particular, excursion of dc-link voltage at no load, effect of pre-existing voltage distortion, impedance mismatches, unequal diode drops on rectifier current sharing and performance, are fully analyzed, Several corrective measures to improve the performance of 12/24­pulse rectifier systems are also discussed. Finally, experimental results on a 460V, 60Hz 400kVA commercial ASD, retrofitted with 12/24pulse rectifier systems are discussed in detail.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.132-135
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• 2001

The design of square pulse generators using pulse forming lines (PFLs) made up of identical L and C, was reviewed in this study. 14 different types of PFLs were analyzed utilizing PSpice simulation results. These PFLs were characterized with respect to their distinct features: the number of forming lines (single or double), the circuit relationship between PFL and load (parallel or series), the types of energy storage (voltage source, current source or a combination of both). The characteristic impedances, output parameters such as pulse width, voltage and current magnitudes, and powers were derived for each scheme. The merits and demerits of the output parameters were also included.

• Journal of the Korean Electrochemical Society
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• v.13 no.1
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• pp.40-44
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• 2010

In this work, highly uniform size-controlled $Cu_2O$ nanocubes can be successfully formed by means of pulse electrodeposition. The size distribution, crystal structure, and chemical state of deposited $Cu_2O$ nanocubes are characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The phase transition from $Cu_2O$ to Cu can be controlled by constant current electrodeposition as a function of deposition time. In particular, the size of the $Cu_2O$ nanocubes can be controlled using pulse electrodeposition as a function of applied current density.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.5
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• pp.245-250
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• 2001

A new capacitor-input type voltage source rectifier is proposed in this paper. The proposed rectifier is based upon 6-pulse diode rectifier with the addition of an auxiliary circuit. By proper operation of the switches of the auxiliary circuit, the input voltage waveform has 18-pulse characteristics and the input current becomes almost sinusoidal due to input ac reactors. The operating principle along with current analysis and input voltage waveform synthesis is described. The experimental results from a laboratory prototype verify the proposed concept.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.10a
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• pp.155-155
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• 2009

The copper plating was deposited by pulse reverse current (PRC) method with additives. The all specimens were first immersted in 10% H2SO4 for 10 minutes, and then were rinsed with deionized water. The current densities of forward pulse were 400mA/$cm^2$, and those of reverse pulse were 1900mA/$cm^2$ and 100mA/$cm^2$. Results are compared for different additives for pulse plating conditions. When it added in Only CH4N2S (TU) or only C10H13NO3S (SVH), the effect of surface side growth of Cu was not different. But when it added in TU and SVH, surface side growth of Cu decreased. Polarization curves were measured from OCP to -0.7 V at a rate of 1mV/sec. Each specimen was observed under the PHENOM to see surface morphology.

• Journal of Power Electronics
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• v.1 no.2
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• pp.71-77
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• 2001

This paper proposes a new zero-current switching (ZCS) pulse-width modulation (PWM) switch cell that has no additional conduction loss of the main switch. In this cell, the main switch and the auxiliary switch turn on and turn off under zero current condition. The diodes commutate softly and the reverse recovery problems are alleviated. The conduction loss and the current stress of the main switch are minimized, since the resonating current stress of the main switch are minimized, since the resonating current for the soft switching does not flow through the main switch. Based on the proposed ZCS PWM switch cell, a new family of DC to DC PWM converters is derived. The new family of ZCS PWM converters is suitable for the high power applications employing IGBTs. Among the new family of DC to DB PWM converters, a boost converter was taken as an example and has been analyzed. Design guidelines with a design example are described and verified by experimental results from the 2.5 kW prototype converter operating at 40 kHz.