• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2556-2558
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• 1999

We present voltage-source inverter for variable speed of washing machine. In the case of previous washing machines only on/off contol of motor was satisfied but these days the desire of customers moves to more silent and energy saving machine. Therefore many white goods manufacturers consider variable driving methods of motor. Nowadays variable speed Induction motors powered by inverters are becoming more and more popular. In this paper the principles of constant V/F control of Induction motor used in washing machine and space vector PWM technique are reviewd. Implementation issues such as command voltage generation, switching pattern determination, speed and power measurement are also presented. Experimental results are included in the end of the paper.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 E
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• pp.1708-1710
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• 1998

In this study, several experiment is executed to analyze properties of Electrodeless Discharge Lamp using H-Discharge. 1. The operating frequency of this lamp is $2.45{\sim}2.65$[MHz] 2. The color of light is mild-white. And, it is shifted in the direction of red in low temperature. 3. In ambient temperature under $10^{\circ}C$, luminous efficiency is decreased precipitously. Therefore, research for improvement discharge-characteristic in low temperature need. 4. Discharge-characteristic stable between $160{\sim}240$[V]. And, luminous output is inverse proportion to coil-voltage. 5. When input-voltage is decreased continuously unstable section exist.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 학술대회 논문집 전문대학교육위원
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• pp.98-101
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• 2002

The switching-mode power converter has been widely used because of its features of high efficiency and small weight and size. These features are brought by the ON-OFF operation of semiconductor switching devices. However, this switching operation causes the surge and EMI(Electromagnetic Interference) which deteriorate the reliability of the converter themselves and entire electronic systems. This problem on the surge and noise is one of the most serious difficulties in AC-to-DC converter. In the case of carrier frequency selection, output-voltage of steady state and transient state is fully regulated. A RPWM control method was proposed in order to smooth the switching noise spectrum and reduce it's level. Experimental results are verified by converter operating at 300V/1kW with 5%${\sim}$30% white noise input. Spectrum analysis is performed on the Phase current and the CM noise voltage. The former is measured with Current Probe and the latter is achieved with USN. which are connected to the spectrum analyzer respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.66-67
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• 2007

We have developed reflective information display using opposite-charged two particles. An appropriate amount of both the yellow and the black powers are putted between the ITO patterned glass substrate separated with cell gap. The rib maintains the cell gap and prevents the interference between the pixels. When a negative voltage is applied to the upper ITO electrode, the positively charged black powder moves to the upper electrode viewing a black appearance. In case of positive voltage is applied to this electrode white particle is observed. So we analyzed the electrical and optical properties of our charged particle type display panel.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.940-941
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• 2015

LCD (liquid crystal display) industry is needed to goods of high reliability and is interested in products without harmful material. In this experiment, we made the LED backlight unit for Automotive-navigation. And for making this backlight unit we used to eight side emitting type white LEDs with 1W high power of the lumileds company. We could know that this backlight unit releases to 6500 nit in 14W power consumption and start up voltage time is under the15ms in the ambient temperature $-20^{\circ}C$.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.740-743
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• 2005

The discussion of this study is that we proposed a new construction to improve the potency of LCOS projection monitor. We suggest a new construction that uses special optics coating to reduce the green channel and obtains a purer white field. Compared with the voltage method to adjust on the monitor, we can get higher contrast gradient.

• Bulletin of the Korean Chemical Society
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• 제32권spc8호
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• pp.2899-2905
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• 2011

We have demonstrated that TPyPA can be used as an efficient multi-functional material for OLEDs; hole transporting material (HTL), blue and white-light emitter. The device based on TPyPA as the HTL exhibited an external quantum efficiency of 1.7% and a luminance efficiency of 4.2 cd/A; these values are 40% higher than the external quantum efficiency and luminance efficiency of the NPD-based reference device. The device based on TPyPA as a blue-light emitter exhibited an external quantum efficiency of 4.2% and a luminance efficiency of 5.3 $cdA^{-1}$ with CIE coordinates at (0.16, 0.14), the device based on TPyPA as a white-light emitter exhibited an external quantum efficiency of 3.2% and a luminance efficiency of 7.7 $cdA^{-1}$ with CIE coordinates at (0.33, 0.39). Also, TPyPA-based organic solar cell (OSC) exhibited a maximum power conversion efficiency of 0.35%. TPyPA-based organic thin-film transistors (OTFTs) exhibited highly efficient field-effect mobility (${\mu}_{FET}$) of $1.7{\times}10^{-4}cm^2V^{-1}s^{-1}$, a threshold voltage ($V_{th}$) of -15.9 V, and an on/off current ratio of $8.6{\times}10^3$.

• 대한전자공학회논문지TE
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• 제39권2호
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• pp.11-16
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• 2002

본 논문은 백색유기발광소자를 구현하기 위해서 빛의 3원색인 적, 녹, 청색의 형광색소를 적절하게 배합하여 단일층 백색광을 얻었다. 개별적인 적색, 녹색, 청색 유기고분자 발광소자의 성능이 가장 우수한 특성을 조사한 후 최적화된 값으로 백색유기발광소자를 제작하였다. PVK와 Bu-PBD를 각각 70wt%, 30wt%로 혼합한 용액에 Nile Red(0.015mol%), Coumarin6(0.04mol%), TPB(3mol%)를 각각 첨가하여 백색발광소자를 제작하였을 때 구동전압이 20V에서 휘도 785cd/$m^2$, 색좌표가 (0.32, 0.34)인 백색광을 얻었다

• 한국초전도ㆍ저온공학회논문지
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• 제22권4호
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• pp.62-66
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• 2020

We fabricated superconducting quantum interference devices (SQUIDs) based on Nb Josephson junctions, and characterized the key parameters of the SQUIDs. The SQUIDs are double relaxation oscillation SQUIDs (DROSs) having larger flux-to-voltage transfer coefficient than the standard DC-SQUIDs. SQUID sensors were fabricated by using Nb junction technology consisted of a DC magnetron sputtering and a conventional photolithography process. In multichannel SQUID systems for whole-head magnetoencephalography measurement with a helmet-type SQUID array, we need about 336 SQUID sensors for each system. In this paper, we fabricated a few hundred SQUID sensors, measured the critical current, flux modulation voltage and decided if each tested SQUID can be used for the multichannel systems. As the criterion for the acceptance of the sensors, we chose the critical current and amplitude of the modulation voltage to be 8 ㎂ and 80 ㎶, respectively. The average critical current of the SQUIDs was 10.58 ㎂. The typical flux noise of the SQUIDs with input coil shorted was 2 μΦ0/√Hz at white region.

• Journal of Electrical Engineering and Technology
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• 제5권1호
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• pp.116-128
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• 2010

Modeling of the three phase electric arc furnace and its voltage flicker mitigation are the purposes of this paper. For modeling of the electric arc furnace, at first, the arc is modeled by using current-voltage characteristic of a real arc. Then, the arc random characteristic has been taken into account by modulating the ac voltage via a band limited white noise. The electric arc furnace compensation with static VAr compensator, Thyristor Controlled Reactor combined with a Fixed Capacitor bank (TCR/FC), is discussed for closed loop control of the compensator. Instantaneous flicker sensation curves, before and after accomplishing compensation, are measured based on IEC standard. A new method for controlling TCR/FC compensator is proposed. This method is based on applying a predictive approach with closed loop control of the TCR/FC. In this method, by using the previous samples of the load reactive power, the future values of the load reactive power are predicted in order to consider the time delay in the compensator control. Also, in closed loop control, two different approaches are considered. The former is based on voltage regulation at the point of common coupling (PCC) and the later is based on enhancement of power factor at PCC. Finally, in order to show the effectiveness of the proposed methodology, the simulation results are provided.