• Proceedings of the KIEE Conference
• /
• 1998.07e
• /
• pp.1773-1775
• /
• 1998

This paper deals with the pulse generator using PFN(Pulse Forming Network), and its operation characteristics and application. Two kinds of pulse generator were composed of the best appropriate condition circuit. The output current of the one pulse generator has the rise time of 28 ns and the pulse duration of $7{\mu}s$. The other pulse generator has high current of about 2kA. By use of the former generator with rapid rise time, the impulse impedance characteristic of ground electrodes was investigated with measuring the ground potential rise when the pulse current was injected into the ground electrode.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.2 no.1
• /
• pp.82-86
• /
• 2002

It is demonstrated that the conventional current-pulse laser drivers are not adequate in driving VCSELs operating at multi-Gb/s speeds. Simulation results, including the bonding parasitics, show that high-performance VCSELs are more efficiently driven using voltage-pulse mode of operation. The optical output power is almost doubled in the voltage-mode of operation, while the total electrical power consumption of the transmitter decreases by 20%.

• Women's Health Nursing
• /
• v.14 no.1
• /
• pp.28-35
• /
• 2008

Purpose: The study was performed to evaluate effects of aroma therapy on the anxiety, blood pressure and pulse of uterine leiomyoma patients before surgery and to apply it as the actual nursing intervention. Method: From Aug1st to Nov. 30th, 2007, the experimental group (n=30) and the control group (n=30) were selected in 1 hospital, Busan. Lavender and Bergamot oil mixed together at a 3:2 ratio was applied to the experimental group two times at 8-9 pm the day before surgery and twice 30 minutes before the surgery. Anxiety, VAS, blood pressure, and pulse were measured to evaluate the effects of aroma therapy. The data analysis was done using the SPSS/PC 12.0 program using chi-square test and t-test. Results: Hypothesis 1 was supported. The VAS of the experimental group was lower than control group after aroma therapy. Hypothesis 2 was partly supported. The systolic blood pressure and pulse of experimental group was significantly decreased, but diastolic blood pressure wasn't difference. The VAS, systolic blood pressure and pulse of control group were increased. Conclusion: The study verified that the aroma therapy is a very effective nursing intervention that can reduce anxiety before surgery. It is recommended to apply aroma therapy actively to patients experiencing anxiety before surgery procedure.

• Proceedings of the KIEE Conference
• /
• 2001.04a
• /
• pp.215-217
• /
• 2001

This paper describes an all solid-state switch pulse generator for various applications where square pulse voltage is required. The pulse generator produces various voltage pulses: voltage $5{\sim}100kV$. current $10{\sim}200A$, pulse width $1{\sim}10{\mu}sec$, repetition rate up to 500Hz. The output power is the combination of these parameters up to 10kW. It consists of a DC-DC converter and several pulse generating modules which are connected in series to obtain higher pulse voltage. Each module contains semiconductor switches (IGBT's), energy storage capacitors and control units to trigger switches. The structure and operational principle are described and the protection circuit for reliable operation is suggested. Experimental results show that the pulse generator can be used for applications with nonlinear loads.

• Proceedings of the KIEE Conference
• /
• 2006.07b
• /
• pp.917-918
• /
• 2006

In this paper, a novel new pulse power generatorbased on IGBT stacks is proposed for pulse power application. Proposed scheme consists of series connected 9power stages to generate maximum 60kV output pulse and one series resonant power inverter to charge DC capacitor voltage. Each power stages are configured as 8 series connected power cells and each power cell generates up to 850VDC pulse. Finally pulse output voltage is applied using total 72 series connected IGBTs. The synchronization of gating signal is importantfor series operation of IGBTs. For gating signal synchronization, full bridge inverter and pulse transformer generates on-off signals of IGBT gating and specially designed gate power circuit was used.

• Proceedings of the KIPE Conference
• /
• 2016.07a
• /
• pp.361-362
• /
• 2016

Presented in this paper is the design of a high voltage switch module made up of MOSFETs, pulse transformers and their gate driver circuits compactly fitted onto a single PCB module. The ease by which the switch modules can be configured (series stacking and/or parallel stacking) to meet future load variations allows for flexible operation of this design. In addition, the detailed implementation of the gate driver circuit for reliable and easier switch synchronization is also described in this paper. The stored energy in the capacitor bank of a 15kV, 4.5kJ/s peak power capacitor charger was discharged using the developed high voltage switch, and by experimental results, the operation of the proposed circuit was verified to be effectively used as a switch for pulse discharging.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.53 no.10
• /
• pp.634-640
• /
• 2004

In this paper, the control strategy for high speed operation in light rail transit system is proposed. Recently, the vector control strategy is used to get high capacity control characteristic in low speed area. But Six step mode that is one pulse mode is used in high speed region to use DC link voltage to the maximum. Therefore, in high speed area, the vector control can not be used but scalar control method is used. To get a driving performance to be stabilized, the method of smooth mode change between the low speed and high speed area and PWM control is desired. So this paper proposes the control strategy using vector control include the one pulse mode. And also proposes overmodulation method that makes to change in one pulse mode softly. The performance of traction system will be verified by simulation results using MATLAB and experimental results.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.13 no.3
• /
• pp.7-10
• /
• 1976

To eliminate some difficulties encountered in the operation of $LiNbO_3$ crystal as a Q-switch for generating a single pulse Nd-YAG laser, the operational characteristics of the crystal, was investigated. Also a simple method for solving the difficulties was presented.

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.33B no.10
• /
• pp.139-147
• /
• 1996

In this study a two-stage fast pulse generaor using magnetic switches is proposed. The scheme consist of a switch, an inductor and two pairs of capacitor and saturable inductors, a linear transformer. The basic principle and the operation are described using a set of given parameters. The main issue of the magnetic pulse genration scheme is the system efficiency. This study focuses on the system efficiency improvement using magnetic switches. The voltage compression ratio, energy transfer with respect to core area are investigated. The output voltage and transferred energy as a function of input voltage are also included. Also, an analysis and experiments are performed to verify the porposed topology by implementing a 10[J] class experimental circuit. The efficiency of the transferred energy a tload side is 82%.

• Proceedings of the KIPE Conference
• /
• 2017.07a
• /
• pp.198-199
• /
• 2017

This paper proposed a new control method for supercapacitor (SC) to compensate the pulse load transient and enhance the power quality of dc microgrid. By coordinating the operation frequency, the supercapacitor is controlled to handle the surge current component while the low-frequency current component is dealt with by remaining sources in the system. Based on the state of charge and dc bus voltage level, the SC unit operation mode is automatically decided. Meanwhile, the dc bus voltage level indicates the power demand of the whole system; by regulating the dc bus voltage, the mismatch of power demand is covered by SC unit. The effectiveness of proposed method is verified by experiment prototype formed by two distributed generation and one supercapacitor unit.