• Journal of the korean academy of Pediatric Dentistry
• /
• v.23 no.4
• /
• pp.887-892
• /
• 1996

For the purpose of assessing the utility and cautionary aspects of pulse oximetry of which use is rapidly increased, it was applied to the maladaptive child patients with sedative drugs and evaluated the results. When pulse oximeter was used alone for vital sign monitoring, it was thought impossible to exclude the false alarm or false silence by various causes. To minimize or remove these misunderstanding, operators should have a extensive knowledge not only on the factors affecting the operation of this apparatus but also on the potential of misoperation. To review the present status of increasing risk of hypoxia during the sedation, it was thought unreasonable to solely depend upon this apparatus for vital sign monitoring. By combining with more accurate and auxiliary monitoring devices, pulse oximetry will be of greater value and can meet the clinical needs and conveniences.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.11 no.2
• /
• pp.149-158
• /
• 2006

A soft-switching scheme for the PWM boost converter, ZCT (Zero current transition : ZCT) boost converter Is newly proposed to obtain the desirable features of both the conventional BWM boost and resonant converters such as easy of control, reduced switching losses and stresses, an4 low EMI. In order to achieve the soft-switching action, the proposed scheme employs an auxiliary circuit, which is added to the conventional boost converter and used to achieve soft-switching for both the main switch and the output diode while not incurring any additional losses due to auxiliary circuit itself. The basic operations, in this paper, we discussed and design guidelines are presented. Through a 100kHz, 60-W prototype, the usefulness of the proposed scheme is verified.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.23 no.4
• /
• pp.256-264
• /
• 2018

This paper proposes a three-bridge LLC resonant converter with auxiliary switches for a wide output voltage control range. This converter can be controlled in two ways to achieve a wide controllable output voltage control range of $V_o$ to $3V_o$. The first control mechanism is achieved through the pulse width modulation (PM) of the auxiliary switches and primary switching devices, while the second control mechanism is achieved through the frequency modulation (FM) of the primary switching devices that are configured to operate in the full-bridge switching mode when the auxiliary switches are turned off. The feasibility of using the proposed converter is verified by the results of an experiment with a 2kW prototype.

• Journal of Power Electronics
• /
• v.18 no.4
• /
• pp.965-974
• /
• 2018

A new zero-voltage-switching (ZVS) push-pull pulse-width modulation (PWM) converter is proposed in this paper. The wide ZVS condition for all of the switches is obtained by utilizing the energy stored in the output inductor and magnetizing inductance. As a result, the switching losses can be dramatically reduced. A simple auxiliary circuit including two small diodes and one capacitor is added at the secondary side of a high frequency (HF) transformer to reset the primary current during the circulating stage and to clamp the voltage spike across the rectifier diodes, which enables the use of low-voltage and low-cost diodes to reduce the conducting and reverse recovery losses. In addition, there are no active devices or resistors in the auxiliary circuit, which can be realized easily. A detailed steady operation analysis, characteristics, design considerations, experimental results and a loss breakdown are presented for the proposed converter. A 500 W prototype has been constructed to verify the effectiveness of the proposed concept.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2005.07a
• /
• pp.175-178
• /
• 2005

The spatio-temporal behaviors of Infra Red(IR) emission images of the sustain discharges were observed in AC PDP with various coplanar-gaps and auxiliary electrode. When the height of barrier rib was fixed, IR intensity of the sustain discharges in AC PDP did not increase with increase of coplanar-gap. The IR efficiency of sustain discharges showed the similar behavior with the IR intensity. The IR intensity had its maixmum value when the coplanar-gap was $200\;{\mu}m$ and the height of barrier rib was $150\;{\mu}m$. It was also found that the auxiliary electrode in the front plate enhanced IR emission during sustain discharge when the pulse was applied to the auxiliary electrode.

• Journal of Welding and Joining
• /
• v.33 no.4
• /
• pp.24-29
• /
• 2015

The current waveform was analysed to monitor the weld quality in real time process. The acquired current waveform was discretely analysed for the top and bottom limits of peaks as well as the pulse frequency measurement. Fast Fourier Transform was implemented in the program to monitor the pulse frequency in real time. The developed algorithm or program was tested for the validation purpose. The cross-section of weld profile was compared to the current waveform profile to correlate the monitored signal and the actual parts. Pulse frequency was also used as auxiliary tool for the quality monitoring. Based on the results, it was possible to evaluate the quality of welding by measure the current waveform profile and frequency measurement.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.179-185
• /
• 2005

This paper presents a novel circuit topology of a high efficiency single-phase power conditioner. This power conditioner is composed of time-sharing sinewave absolute pulse width modulated boost chopper with a bypass diode in the first power processing stage and time-sharing sinewave pulse width modulated full-bridge inverter in the second power processing stage operated by time-sharing dual mode pulse pattern control scheme. The unique operating principle of the two power processing stage with time-sharing dual mode sinewave modulation scheme is described with a design example. This paper proposes also a sinewave tracking voltage controlled soft switching PWM boost chopper with a passive auxiliary edge-resonant snubber. The new conceptual operating principle of this novel power conditioner related to new energy utilization system is presented and discussed through the experimental results.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.52 no.3
• /
• pp.133-139
• /
• 2003

In this paper, a new control scheme of Class-E inverter for Induction Heating (IH) Jar applications with clamped voltage characteristics using Pulse-Frequency-Modulation (PFM) is introduced. To reduce the voltage stress of switch, the proposed PFM control scheme doesn't need any auxiliary circuit in comparison to a family of Active Clamped Class-E (ACCE) inverter. It can decrease voltage stress of switch through modulation of switching frequency. The Class-E inverter using the proposed control scheme has the advantage of not only the same output power when it is compared with a Hybrid-Active Clamped Class-E (Hybrid-ACCE) inverter but also Zero-Voltage-Switching (ZVS), which are characteristics of conventional Class-E and ACCE inverter. The control principles and analysis of proposed method are explained in detail and its validity is verified through simulation and experimental results.

• Proceedings of the KIPE Conference
• /
• 2001.10a
• /
• pp.256-260
• /
• 2001

This paper presents boost and buck and buck-boost DC-DC converter circuit topologies of high-frequency soft switching transition PWM chopper type DC-DC high power converters with a single auxiliary passive resonant snubber. In the proposed boost power converter circuits operating under a principle of ZCS turn-on and ZVS turn-off commutation schemes, the capacitor and inductor in the auxiliary passive resonant circuit works as the loss less resonant snubber. In addition to this, the switching voltage and current peak stresses as well as EMI and RFI noises can be basically reduced by this single passive resonant snubber. Moreover, it is proved that converter circuit topologies with a passive resonant snubber are capable of solving some problems of the conventional hard switching PWM processing based on high-ferquency pulse modulation operation principle. The simulation results of this converter are discussed as compared with the experimental ones. The effectiveness of this power converter with a single passive resonant snubber is verified by the 5kW experimental breadboad set up.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.7-12
• /
• 2006

The high efficacy concept, featuring in this study an auxiliary electrode and a 200 ${\mu}m$ coplanar gap, is applied to AC-PDPs with a stripe - type and a closed - type barrier rib, respectively. The roles of the pulses applied to the auxiliary electrode create additional excitation during the sustain period and reduce a discharge current that flows into the display cells. The efficacy of the proposed panel with the closed barrier rib has maximum values when the auxiliary pulse voltage is 50 volts and 80 volts for the Ne+4%Xe and Ne+20%Xe gas-mixtures, respectively. The maximum luminous efficacy is more than 10 lm/W in terms of the measurement of the discharges in VGA resolution ($540{\mu}m{\times}720{\mu}m$) and the green cells.