• Transactions on Electrical and Electronic Materials
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• 제17권6호
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• pp.359-362
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• 2016

In the PV (Photovoltaic) power system, a junction box collects the DC voltage generated from the PV module and transfers it to the PCS (power conditioning system). The junction box prevents damage caused by the voltage difference between the serially connected PV modules and provides convenience while repairing or inspecting the PV array. In addition, the junction box uses the diode to protect modules from the inverse current when the PV power system and electric power system are connected for use. However, by using the reverse blocking diode, heat is generated within the junction box while generating electric power, which decreases the generating efficiency, and causes short circuit and electric leakage. In this research, based on the purpose of improving the performance of the PV module by decreasing the heat generation within the junction box, a junction box with a built-in bypass circuit was designed/manufactured so that a certain capacity of current generated from the PV module does not run through the reverse blocking diode. The manufactured junction box was used to compare the electric power and heating power generated when the circuit was in the bypass/non-bypass modes. It was confirmed that the electric power loss and heat generation indicated a decrease when the circuit was in the bypass mode.

• 한국전자파학회논문지
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• 제11권8호
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• pp.1386-1391
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• 2000

본 논문에서는 다이오드의 비선형 특성을 선형화하고 온도에 따른 특성 변화를 보상하는 방법에 대해 연구하였다. 입력전력에 대한 다이오드의 비선형성을 선형화학 위해 Square root 회로를 사용하였으며, 온도에 따른 다이오드의 특성변화를 보상하기 위해서는 2개의 동일한 다이오드와 기준전위를 가변시킬 수 있는 OP-Amp를 사용하였다. 그 결과로써, (Square root 회로와 온도보상회로를 이용하여) 설계된 다이오드 전력 검출기는 입력전력이 -6㏈m보다 큰 경우에 0.23$\pm$0.025 V/㏈m의 비율로 선형적으로 출력전력을 검출하였으며, 상온에서 8$0^{\circ}C$까지의 온도변화에 대해 출력전압의 변화없이 안정적으로 동작하였다.

• 한국전자파학회논문지
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• 제26권5호
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• pp.471-482
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• 2015

본 논문에서는 94 GHz Gunn 고정발진기를 설계 및 제작하였고, 이를 이용하여 발진기에 사용된 Gunn 다이오드의 최대 전력을 조사하였다. 94 GHz Gunn 고정발진기는 InP Gunn 다이오드가 사용되었고, WR-10 도파관 구조로 설계 및 제작되었다. 제작된 발진기는 발진주파수 95 GHz에서 12.64 dBm의 출력 전력과 1 MHz 오프셋 주파수에서 -92.7 dBc/Hz의 위상잡음 성능을 보였다. 발진기에 사용된 InP Gunn 다이오드의 최대 전력을 조사하기 위해서 발진기 구조를 턱이 있는 구조로 수정하였다. 그리고 이 턱의 높이를 변화시켜, 발진기가 몇 가지의 다른 부하 임피던스를 갖도록 하였다. 이 몇 가지의 다른 부하 임피던스에 대한 결과로써, 포스트 면에서의 부하 실수부 $G_L$에 대한 발진 신호 $V^2$의 그래프를 얻었다. 이 $G_L-V^2$의 그래프를 이용하여, 바이어스 포스트의 손실이 포함된 Gunn 다이오드의 최대 전력 16.8 dBm을 얻었다. 그리고 short된 Gunn 다이오드와 제로 바이어스 상태의 Gunn 다이오드를 이용하여 바이어스 포스트의 손실을 계산하였다. 바이어스 포스트의 손실을 보상한 InP Gunn 다이오드만의 최대 전력은 95 GHz에서 18.55 dBm이다. 이는 사용된 Gunn 다이오드의 데이터시트에 가까운 결과이다.

• Journal of Power Electronics
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• 제17권2호
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• pp.561-569
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• 2017

Power converter design requires simulation accuracy. In addition to the requirement of accurate models of power semiconductor devices, this paper highlights the role of considering a very good description of the converter circuit layout for an accurate simulation of its electrical behavior. This paper considers a simple experimental circuit including one switching cell where a MOSFET transistor controls the diode under test. The turn-off transients of the diode are captured, over which the circuit wiring has a major influence. This paper investigates the necessity for accurate modeling of the experimental test circuit wiring and the MOSFET transistor. It shows that a simple wiring inductance as the circuit wiring representation is insufficient. An adequate model and identification of the model parameters are then discussed. Results are validated through experimental and simulation results.

• 한국레이저가공학회지
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• 제8권3호
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• pp.21-26
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• 2005

A bonding process between tape-carrier package and a glass panel with anisotropic conductive film (ACF) has been investigated by making use of high power diode laser as a heat source for cure. The results from modeling of process and from optical properties of layers showed that heat absorbed from polyimide film surface and ACF layer is dominant source of curing during laser illumination. Laser ACF bonding has better bonding quality than conventional bonding in view of peel strength, flatness, pressure unbalance and processing time. New ACF bonding processes by making use of high power diode laser are proposed.

• 마이크로전자및패키징학회지
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• 제11권3호
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• pp.71-76
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• 2004

레이저다이오드 냉각을 위해 사용되는 TEC의 소비전력을 3차원 유한요소해석으로 예측하고 실험을 통해 해석결과의 타당성을 검증하였다. 레이저다이오드의 소비전력, 제어온도, 외기온도, 열전달경로의 열저항 등이 고려되었다. 저소비전력 모듈의 설계를 위해 해석결과를 바탕으로 Pellet의 숫자와 치수로 결정되는 TEC 형태에 따른 소비전력특성을 고찰한 결과 Pellet의 숫자가 적으며 접지면적이 작고 길이가 길수록, 즉 열저항이 증가할수록 소비전력은 감소하였다.

• Journal of Power Electronics
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• 제14권2호
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• pp.265-270
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• 2014

In terms of power loss, a MOSFET has two advantages over an IGBT with an antiparallel diode: purely resistive without an offset voltage in conduction and no tail current at turn-off. However, the reverse recovery characteristic of the body diode is so poor that MOSFETs have not yet been available for high-voltage power converters with bidirectional power flow legs. This paper introduces how MOSFETs can be fully applied to high-voltage power converters with bidirectional power flow legs in order to achieve high efficiency. With a bidirectional DC-DC converter with one leg as the simplest example, the basic circuit topology and operating principle are described in detail. The high efficiency and stable operation of the proposed converter are validated through experiments with a 1.5 kW prototype.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2014년도 전력전자학술대회 논문집
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• pp.59-60
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• 2014

In this paper, development of laser diode driver with 2.5kW rating is presented. The driver is configured with interleaved PFC converter, high frequency full bridge DC-DC converter, two laser diode drivers and ${\mu}$-processor based controller. The system has two laser diode drivers for providing high current and low current. High current driver delivers normal output power of diode; low current driver is for providing critical current of diode for long lifetime. Computer simulation and experiment was performed for verification, as the results, developed driver performs well.

• Journal of Power Electronics
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• 제16권2호
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• pp.815-822
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• 2016

The efficiency of light-emitting diode (LED) devices is a significant factor that reflects the capability of these devices to convert electrical power into optical power. In this study, a method for estimating the efficiency of LED devices is proposed. An efficiency model and a heat power model are established as convenient tools for LED performance evaluation. Such models can aid in the design of LED drivers and in the reliability evaluation of LED devices. The proposed estimation method for the efficiency and heat power of LED devices is verified by experimentally testing two types of commercial LED devices.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.333-344
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• 2018

This proposed paper aims for the high efficiency contactless power transfer in household dc power distribution. A 300 W five-level diode clamped multi-level converter with 300 Vdc input dc link bus is employed for the power transferring task and the output voltage range is controlled at 48 Vdc. The inner and outer solenoid coils are used for inductive power transfer (IPT) transformer with the 200 kHz switching frequency for designed power density. Therefore, to achieve the converter efficiency above 95%, the LLC series resonant with fundamental harmonic analysis (FHA) and the calculated switching angles are used as an optimized tool for designing the system resonant tank. The validations of this approached topology are illustrated in both MATLAB/Simulink simulation and implementation.