• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.617-618
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• 2012

Recently as the inactive response characteristics of the existing RCD(Residual Current protective Device) used on low voltage power distribution system, so control of overload and electric short circuit faults, major causes of electrical fires, are not enough. Therefore, this paper is proposed a prevention apparatus using neutral line voltage and semiconductor switching devices for the prevention of electrical disasters in low voltage power distribution system caused by overload or electric short circuit faults. The proposed prevention apparatus confirms the excellent characteristics in response velocity and accuracy in comparison with the conventional circuit breaker(RCD) through various operation performance analysis.

• Journal of Welding and Joining
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• v.17 no.5
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• pp.61-68
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• 1999

For the last two decades, waveform control techniques have been successively developed and applied for the inverter welding machines resulting in the substantial reduction of spatter generated in CO₂ welding. One of the constituents commonly involved in those techniques is to delay the instant of current increase to some extent after the initiation of short-circuiting. Although this technique has been known to be quite effective in reducing the spatter generation through the suppression of is instantaneous short circuiting, the delay time necessary for minimum spatter has not been clearly understood. In this study, the control system for varying the delay time was constructed so that the spatter generation rates could be measured over a wide range of delay time, 0.29-2.0 msec. As a result of this study, it was demonstrated that spatter generation rate(SGR) sharply decreased at delay time of 0.6 msec and longer accompanied with the change in characteristics of short circuit mode from the instantaneous short-circuiting(ISC) dominant to normal short-circuiting(NSC) dominant. Another feature that have been found in current waveform of over 0.6msec was the creation of current pulse right after the arc reignition stage. Because of this current pulses weld pool oscillated in wave-like fashion and it looks like to play an important role in developing short circuiting between electrode and weld pool.

• Journal of the Korean Institute of Telematics and Electronics
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• v.11 no.2
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• pp.33-39
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• 1974

Networks showing often and short stable voltage inversion negative immittance converter(VNIC) characteristics are proposed by simplified equivalent model. Open stable VNIC characteristics can be obtained of controlling the base voltage of common base connection according to output voltage and short stable VNIC characteristics according to input dotage. An unbalanced circuit showing open and short stable characteristics is constructed and ana1ysis. The experimental results are coincident with the calculated within 10% error.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.2
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• pp.141-146
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• 2009

In this paper, a novel harmonic control circuit has been proposed for the design of high-efficiency power amplifier with Si LDMOSFET. The proposed harmonic control circuit haying the short impedances for the second- and third-harmonic components has been used to design the in/output matching network. The efficiency enhancement effect of the proposed harmonic control circuit is superior to the class-F or inverse class-F harmonic control circuit. Also, when the proposed harmonic control circuit has been adapted to the input matching network as well as the output matching network, the of ficiency enhancement effect of the proposed power amplifier has increased all the more. The measured maximum power added efficiency (PAE) of the proposed power amplifier is 82.68% at 1.71GHz band. Compared with class-F and inverse class-F amplifiers, the measured maximum PAE of the proposed power amplifier has increased in $5.08{\sim}9.91%$.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.925_926
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• 2009

In this paper, a method to cope with short-term blackout is proposed. The proposed method uses a capacitor bank consisting of supercapacitors. A supercapacitor is a good means for short-term energy storage. The proposed circuit is simple and accordingly easy to construct and to control. A prototype is constructed and experimental results are presented.

• Journal of the Korean Solar Energy Society
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• v.30 no.4
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• pp.1-8
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• 2010

The mechanical parts of small windp ower generator less than 10kW are manufactured in the form of removing most of the accelerators. The braking system to protect blade from damages caused by high wind speed is manufactured in a manner having apparatus system(furling), manual brake or no brake. This study is on braking system in small size wind power generator, and carried out survey as following steps by applying electric braking system which uses armature reaction. We explained the principle of electric braking system and the principle of existing braking system. Also, this paper interpreted short circuit current through open circuit and short circuit, as well as checking brake system's action using armature reaction with real construction of control device.

• Journal of IKEEE
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• v.26 no.3
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• pp.510-514
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• 2022

In this paper, we propose the development of high-sensitivity low-end radiation measuring sensor module. The proposed measurement sensor module is a scintillator + photomultiplier(SiPM) sensor optimization structure design, amplification and filter and control circuit design for sensor driver, control circuit design including short-distance communication, sensor mechanism design and manufacturing, and GUI development applied to prototypes consists of, etc. The scintillator + photomultiplier(SiPM) sensor optimization structure design is designed by checking the characteristics of the scintillator and the photomultiplier (SiPM) for the sensor structure design. Amplification, filter and control circuit design for sensor driver is designed to process fine scintillation signal generated by radiation with a scintillator using SiPM. Control circuit design including short-distance communication is designed to enable data transmission through MCU design to support short-range wireless communication function and wired communication support. The sensor mechanism design and manufacture is designed so that the glare generated by wrapping a reflective paper (mirroring) on the outside of the plastic scintillator is reflected to increase the efficiency in order to transmit the fine scintillation signal generated from the plastic scintillator to the photomultiplier(SiPM). The GUI development applied to the prototype expresses the date and time at the top according to each screen and allows the measurement unit and time, seconds, alarm level, communication status, battery capacity, etc. to be expressed. In order to evaluate the performance of the proposed system, the results of experiments conducted by an authorized testing institute showed that the radiation dose measurement range was 30 𝜇Sv/h ~ 10 mSv/h, so the results are the same as the highest level among products sold commercially at domestic and foreign. In addition, it was confirmed that the measurement uncertainty of ±7.4% was measured, and normal operation was performed under the international standard ±15%.

• Journal of Welding and Joining
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• v.25 no.5
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• pp.4-14
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• 2007

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.2
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• pp.71-80
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• 1999

In this paper, a power MOSFET driver with protection circuits is designed using a 2${\mu}m$ high-voltage CMOS process. For stable operations of control circuits a power managing circuit is designed, and a voltage-detecting short-circuit protection(VDSCP) is proposed to protect a voltage regulator in the power control circuit. The proposed VDSCP scheme eliminates voltage drop caused by a series resistor, and turns off output current under short-circuit state. To protect a power MOSFET, a short-load protection, a gate-voltage limiter, and an over-voltage protection circuit are also designed A high voltage 2 ${\mu}m$ technology provides the breakdown voltage of 50 V. The driver consumes the power of 20 ~ 100 mW along its operation state excluding the power of the power MOSFET. The active area of the power MOSFET driver occupies $3.5 {\times}2..8mm^2$.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.1
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• pp.1-8
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• 2003

When solving the problems of electric power quality the converters with high Power factor are useful for the DC arc furnace power supply. In this paper, resonant converters of 50(60) Hz AC to DC arc described, where in each period of network voltage the capacitor and inductor of an oscillatory circuit are switched from series into parallel and vice versa parametrically. The duration of series and parallel connection and also the transformation ratio are dependent on load. Parallel oscillatory circuit restricts the short circuit current. These converters have high power factor from no-load to short-circuit and fit very well to supply are furnaces.