• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2000년도 전력전자학술대회 논문집
• /
• pp.299-304
• /
• 2000

In this paper we investigate accurately the input-output characteristic of single-phase diode rectifier. The diode rectifier has some advantages of simplicity cost and high-efficiency. But it has some defects which THD of input current low PF and voltage drop of output side. In order to compensate it we analyzed using the parameter variation and introduced capacitor insertion method for reducing the distortion and increasing the PF.

• 한국광학회:학술대회논문집
• /
• 한국광학회 2001년도 하계학술발표회
• /
• pp.160-161
• /
• 2001

A diode laser system has been developed for the refractory glaucoma therapy. The diode lasers have merits in clinical usage including reduction of beam dispersion, higher absorption such as in melanin pigment, and lower complication in treatment. We present the system specification of laser diodes in 810mm with 3W power, which is delivered into the optical fiber core of 600${\mu}{\textrm}{m}$.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
• /
• pp.625-627
• /
• 2007

We demonstrated high power efficiency and long lifetime in organic light-emitting diode (OLED) using new electron transport materials (ETMs). Electroluminescent device with these ETMs showed lower driving voltage than that with $Alq_3$. The device lifetime with a new ETM was 2 times longer than that with $Alq_3$.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2001년도 전력전자학술대회 논문집
• /
• pp.514-519
• /
• 2001

Most of inverters adopt a diode rectifier as an input stage, which has very simple and rugged structure and therefore low cost. In order to properly design the 3-phase diode rectifier with an output smoothing capacitor and input inductors, it is necessary to fully simulate the system due to its nonlinear characteristics. Therefore this paper describes the operating behaviors including the current commutation in detail by using the proposed equivalent circuit, and also proposes the Simulink-based model of the system. The simulation results show the validity of the proposed model in all operating conditions.

• 반도체디스플레이기술학회지
• /
• 제21권1호
• /
• pp.127-131
• /
• 2022

The effect of bypass diodes on the output energy of solar cells was investigated under the condition of partial shading. The maximum power point was estimated using the perturbation & observation algorithm, taking into account the correlation effect between the arrangement and number of bypass diodes. The performance of the bypass diode was tested under the consideration of the partial shading effect and simulated using a Matlab/Simulink.

• 전력전자학회논문지
• /
• 제14권6호
• /
• pp.514-521
• /
• 2009

본 논문은 다이오드 클램프형 3-레벨 IGBT 인버터에 적용 가능한 새로운 방식의 과전압 방지 스너버에 관한 것이다. 일반적으로 전력변환장치는 스위칭 소자에 발생하는 과전압을 감소시키기 위해 스너버 회로를 포함하고 있다. 하지만 다이오드 클램프형 멀티레벨 인버터는 스위칭 소자가 직렬로 연결되어 있기 때문에 과전압 방지 스너버를 구성하기 힘든 문제점이 있다. 본 논문에서는 스텝-다운 DC-DC 컨버터에 적용 가능한 과전압 방지 스너버의 특성을 이용하여 다이오드 클램프형 3-레벨 인버터에 과전압 방지 스너버를 구성하려 할 때 발생하는 문제점을 분석하고 분석 결과를 토대로 다이오드 클램프형 3-레벨 인버터에 적용할 수 있는 새로운 구조의 스너버를 제안하였다. 제안한 방식에 대한 특성을 해석하였고, 실험을 통하여 효용성을 입증하였다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2003년도 춘계학술대회 논문집
• /
• pp.1663-1667
• /
• 2003

This thesis is on tile development of LD(Laser Diode) chip tester and the control system based on graphical programming language(LabVIEW) to control the equipment. The LD chip tester is used to test the optic power and the optic spectrum of the LD Chip. The emitter size of LD chip and the diameter of the receiver(optic fiber) are very small. Therefore, in order to test each chip precisely, this tester needs high accuracy. However each motion part of the tester could not accomplish hish accuracy due to the limit of the mechanical performance. Hence. an image processing with machine vision was carried out in order to compensate for the error. and also a load test was carried out so as to reduce tile impact of load on chip while the probing motion device is working. The obtained results were within ${\pm}$5$\mu\textrm{m}$ error.

• Current Optics and Photonics
• /
• 제1권2호
• /
• pp.113-117
• /
• 2017

With the increasing use of high-power laser diode bars (LDBs) and stacked LDBs, the issue of thermal control has become critical, as temperature is related to device efficiency and lifetime, as well as to beam quality. To improve the thermal resistance of an LDB set, we propose and analyze a bypass heat sink with a top canopy structure for an LDB set, instead of adopting a thick submount. The thermal bypassing in the top-canopy structure is efficient, as it avoids the cross-sectional thermal saturation that may exist in a thick submount. The efficient thickness range of the submount in a typical LDB set is guided by the thermal resistance as a function of thickness, and the simulated bypassing efficiency of a canopy is higher than a simple analytical prediction, especially for thinner canopies.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
• /
• pp.336-336
• /
• 2011

AMOLED에 대한 관심이 높아짐에 따라 LTPS (Low Temperature Poly Silicon) TFT에 대한 연구가 활발히 이루어지고 있다. 다결정 실리콘은 단결정 실리콘에 비해 100 cm2/V 이상의 이동도를 보이는 우수한 특성으로 인해 AMOLED 디스플레이에 적합하며 여러 기업에서 LTPS 공정을 이용한 TFT제작을 연구 중이다. LTPS 공정은 현재 ELA (Excimer Laser Annealing) 방식으로 대면적 유리기판에 ELA 방법을 적용함에 있어 설비투자 비용이 지나치게 높아진다는 단점을 가지고 있다. 설비투자 비용의 문제점을 해결하기 위해 Diode Laser을 이용하여 Annealing하는 방법에 대해 연구하였다. 본 연구는 Diode Laser Annealing 방식을 이용하여 poly-Si을 구현하였다. 단결정 실리콘을 제작하기 위해 ICP-CVD장비를 이용하여 150$^{\circ}C$에서 SiH4, He2 혼합, He/SiH4의 flow rate는 20/2[sccm], RF power는 400 W에서 700 W으로 가변, 증착 압력은 25mTorr으로 하였다. 940 nm 파장의 30 W Diode Laser를 8 mm Spot Size로 a-Si에 순간 조사하여 결정화, 그 결과 grain을 형성한 polycrystalline 구조를 확인하였다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제48권11호
• /
• pp.640-645
• /
• 1999

This paper proposes a new series-connected diode rectifier which draws sinusoidal input currents. The proposed rectifier system is configured by adding an auxiliary circuit to the conventional 12-pulse series-connected diode rectifier and employing a current injection technique. A low kVA($0.02P_{\circ}$(PU) ) active current source injects a triangular current into the interphase reactor of the diode rectifier. The current injection results in near sinusoidal input current from the utility with less than 1% THD. The resulting system is suitable for high voltage and high power applications. Experimental and simulation results are provided from a 220V, 3kVA prototype rectifier system.