• Journal of the Korean institute of surface engineering
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• v.37 no.3
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• pp.152-157
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• 2004

Ti-Al-N ($Ti_{75}$ $Al_{25}$ N) and Ti-Al-Si-N ($Ti_{69}$ $Al_{23}$ $Si_{8}$N) coatings synthesized by a DC magnetron sputtering technique were studied comparatively with respect to phase characterization and high-temperature oxidation behavior. $Ti_{69}$ $Al_{23}$ $Si_{ 8}$N coating had a nanocomposite microstructure consisting of nanosized(Ti,Al,Si)N crystallites and amorphous $Si_3$$N_4$, with smooth surface morphology. Ti-Al-N coating of which surface $Al_2$$O_3$ layer formed during oxidation suppressed further oxidation. It was sufficiently stable against oxidation up to about $700^{\circ}C$. Ti-Al-Si-N coating showed better oxidation resistance because both surface Ab03 and near-surface $SiO_2$ layers suppressed further oxidation. XRD, GDOES, XPS, and scratch tests were performed.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.5
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• pp.643-648
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• 2011

In this study, SMPS driven LED traffic signal light for Large-scale traffic such as railroad and airport was designed and its electrical and EMI characteristics were measured. The output current of the LED module driven by SMPS was 1.67A for AC and DC input voltage over 10V. The conducted emission measured over 0.15~30MHz frequency range was lower than the allowed quasi-peak and average level, and the radiated noise measured over 30~1000MHz frequency range showed $23.96dB{\mu}V/m$ at 59.96MHz.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.2
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• pp.103-107
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• 2009

PI controller is widely used as voltage control system of generator. However when a generator system has various characters of continuance, a new PI parameter decision for accurate control is a hard task as method of solving this problem, in this paper, the method to generator voltage control using Neural Network self adaptive control is presented. A property continuous feedback control gain of voltage control system is decided by a rule of delta learning. The function of proposed control method is verified by voltage control experiment results of DC generator.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.12
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• pp.136-145
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• 2009

This paper proposes control methods and simulation models of a driving system, which consists of converters and inverters, for high speed trains employing multi-level power converters. The control method of a single phase three-level converter for high-speed trains is designed to use DC values instead of instantaneous current values which are usually used in single-phase application, so that it results in a fast and robust voltage control response. In addition, simulation models of Space Vector Pulse Width Modulation (SVPWM) for single phase three-level converters as well as three level inverters are proposed. Experimental results demonstrate the validity of the simulation model for three-level inverters.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.6
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• pp.89-95
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• 2009

A new class of electronically commutated brushless motor, the flux-switching motor(FSM) is gradually emerging in power tools and household appliances especially fan and pump application because of green policy. This motor offers advantages of high-power density and relatively high efficiency compare with induction motor, low cost and simple motor structure compare with bldc motor. This paper presents the principle of the FSM and design of the 12/6 pole FSM drive system for fan application. Finally, test results of the prototype motor are provided to verify a validity of the fan application with TMS320F2812 DSP and inverter.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.1
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• pp.53-60
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• 2010

This paper dealt with the acoustic detection of partial discharge (PD) in insulation oil for insulation diagnostics of oil immersed transformers. Electrode systems such as needle to plane, plane to plane, and floating were fabricated to simulate some defects in transformers. A wide band acoustic emission(AE) sensor with the frequency ranges of 100 kHz~1 MHz and a narrow band AE sensor with the resonant frequency of 140 kHz were used in the experiment. Also, a decoupler and an amplifier were designed to detect and amplify the acoustic signal only. The decoupler separates acoustic signal from DC source without any distortion, and the amplifier has the gain of 40 dB in frequency ranges of 11 kHz~4 MHz. In the experiment, frequency components and propagation characteristics of acoustic signal were analyzed, and an algorithm of positioning of PD occurrence by the time difference of arrival was proposed. From the results, the frequency components of the acoustic signal exist from 50 kHz to 200 kHz and the positioning error of PD calculated by three AE sensors was within 1%.

• Journal of the Korea Society of Computer and Information
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• v.23 no.1
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• pp.91-102
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• 2018

The purpose of this study is to develop an excellent bodice prototype that is adapted to the body shape of middle-aged women using 3D measurement data. In the evaluation of appearance, S pattern 4.00, B pattern 2.80, E pattern 2.40, L pattern 1.40 were shown in order, and the best fit of S pattern was evaluated as excellent. As a result of looking at the color distribution chart to find out the amount, E pattern and S pattern were not space in the front bust, armhole, and the back waist line. The B pattern and the L pattern were marked in blue because of insufficiency space in the back neck. As a result of evaluation the amount of air gap in the clothing, the air gap of the bust was 0.12, which is the largest pattern of B. Next, the L pattern appears as a tight circle with smallest air gap in the order of the S pattern 0.096, the E pattern 0.08, and the L pattern 0.003. The S pattern was evaluated to be the most appropriate for the body shape of middle-aged women. But the waist and back were slightly tight. Middle-aged women have larger shoulder-related items and larger waist circumference. Therefore, when you set the perimeter item, you should add 1-2cm of space amount and give extra space to the circumference area.

• Journal of IKEEE
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• v.23 no.2
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• pp.407-412
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• 2019

Many industrial regions has used and extended the application of LED driver because of many advantage. Specially, due to the simplicity, miniaturization and power density, the flyback converter is selected by a lot of power engineer. Also, the electrolytic capacitor in this converter is used for the constant DC voltage of the converter because of the sufficient capacitance and the economic price. However, because of the characteristics of the electrolytic capacitor and ripple currents on the converter. the expected lifetime of the LED driver is more and more shorted. In this paper, a single-stage CCM PFC flyback converter with the film capacitor is suggested to extended the lifetime of the LED driver. In addition, the proposed converter with the LC filter is decreased the ripple current of the converter output.

• Journal of IKEEE
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• v.23 no.1
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• pp.224-229
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• 2019

Seat of automobile is required to support the comfort to driver and passenger during the driving. The control method of the seat position is changed from manual type to power type, which means using the motor to increase the comfort of the driver. By using the motor, several problems, such as vibration, noise, and over-current, appeared. These problems can be reduced through the control of seat motor. In this study, a control technology of four control variables, which determine profile of the input voltage applying to the seat motor, is proposed to generate the current profile having soft-start and soft-stop. The current flowing through the coil by input voltage is described by mathematical modeling of power seat. It is confirmed that optimized current profile having soft-start and soft-stop can be generated from simulation using the mathematical model.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.6_2
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• pp.989-998
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• 2020

Recently, demands for large-capacity electronic loads are increasing in various industries such as a reliability test for the performance of a DC power supply device or a dummy-load for improving the stability of an independent microgrid to be actively built in the future. The electronic load required in these various fields requires an operation such as a continuously variable resistance load while minimizing the switching harmonic component generated in the electric load current in order to reduce the influence of interference from the load peripheral device. Electronic loads require a system that minimizes switching current ripple for load control. Therefore, in this paper, we propose a three-level module converter structure to reduce the current ripple of an electronic load, and a multilevel interleaved power converter topology to reduce the current ripple. The validity of the proposed electronic load, 3-level 6 interleaver converter, was verified by simulation and experiment. In addition, the user's convenience was provided by applying the emotional command curve interface method.