• Journal of Power Electronics
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• 제12권4호
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• pp.519-527
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• 2012

A high step-down multiple-output LED driver is proposed in this paper. Firstly, the derivation of the driver with dual-output is presented and its operation principle and steady state performance are analyzed in detail. Secondly, a high step-down N-channel LED driver is proposed and its current auto-balance characteristic and step-down ratio are analyzed. Finally, an experimental prototype is built and the experimental results are given. The theoretical analysis and experimental results show that the proposed driver has the following virtues: First, if load balancing is achieved, the voltage gain is 1/N that of a Buck driver, where N is the number of channels. Second, each output automatically has an equal output current, without requiring more current close-loop control circuits than a Buck driver. Last, the voltage stresses of the switches and diodes are lower than those of a Buck driver, meaning that lower voltage switches and diodes can be used, and a higher efficiency can be expected.

• Journal of Power Electronics
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• 제15권1호
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• pp.86-95
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• 2015

An active clamp high step-up boost converter with a coupled inductor is proposed in this paper. In the proposed strategy, a coupled inductor is adopted to achieve a high voltage gain. The clamp circuit is included to achieve the zero-voltage-switching (ZVS) condition for both the main and clamp switches. A rectifier composed of a capacitor and a diode is added to reduce the voltage stress of the output rectifier diode. As a result, diodes with a low reverse-recovery time and forward voltage-drop can be utilized. Since the voltage stresses of the main and clamp switches are far below the output voltage, low-voltage-rated MOSFETs can be adopted to reduce conduction losses. Moreover, the reverse-recovery losses of the diodes are reduced due to the inherent leakage inductance of the coupled inductor. Therefore, high efficiency can be expected. Firstly, the derivation of the proposed converter is given and the operation analysis is described. Then, a steady-state performance analysis of the proposed converter is analyzed in detail. Finally, a 250 W prototype is built to verify the analysis. The measured maximum efficiency of the prototype is 95%.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.970-977
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• 2014

In this paper, the artificial neural network is used to predict the junction temperature of the IGBT power module, by measuring the temperature sensitive electrical parameters (TSEP) of the module. An experiment circuit is built to measure saturation voltage drop and collector current under different temperature. In order to solve the nonlinear problem of TSEP approach as a junction temperature evaluation method, a Back Propagation (BP) neural network prediction model is established by using the Matlab. With the advantages of non-contact, high sensitivity, and without package open, the proposed method is also potentially promising for on-line junction temperature measurement. The Matlab simulation results show that BP neural network gives a more accuracy results, compared with the method of polynomial fitting.

• 한국압력기기공학회 논문집
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• 제8권2호
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• pp.21-25
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• 2012

Functional Equipment Group(FEG) of Nuclear Power Plant(NPP) is the bundling of multiple equipment subcomponents around a major equipment with a common system isolation characteristic or out-of-service consideration. The main purpose of FEG is to reduce out-of-service time to enhance maintenance effectiveness. KHNP(Korea hydro & Nuclear Power Co.) needs to develop these FEGs to successfully perform On-line Maintenance(OLM) which will be expected to institute in the future. Recently, there has been growing interest in OLM in KHNP. The aim of this paper is to suggest the way of FEG development and to build the FEG of MCR(Main Control Room) HVAC(Heat, Ventilation and Air Conditioning) system. The results of this study might be make good use of OLM and be helpful for equipment maintenance for MCR HVAC system.

• 한국철도학회논문집
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• 제9권4호
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• pp.504-509
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• 2006

Currently, most of TDIS(Train Destination Indicator System) is operated colored-LED type equipment in Korea. This current LED type TDIS equipment has not graceful display and causes passenger's fatigues because of the LED module inherent characteristics as a display light source, high power consumption, high operating and maintenance costs, and et al. To address these several, we are developed new colored-LCD type TDIS equipment. According to our developed new TDIS equipment, we can achieve high resolution and graceful color stone of information display. Thus high graded service are able to provide to passengers. In addition, LCD module decreases power consumption, and it can be used permanently by changing only backlight in comparison with conventional equipment. Therefore we can decrease the maintenance cost and extend durability-period of TDIS equipment using new equipment.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 추계학술대회 논문집
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• pp.227-228
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• 2013

The paper is related to smart maximum power system based on program logic. Especially, this system compares the total demand power with the target power by using the signal from the digital kilo watt meter. Based on the power information by the maximum power control equipment the consumed future power is anticipated. In addition, through consumed future power the controllable target power is set, and it applies on the maximum power control equipment. User or manager would control the load efficiently through the simple programming which could control load based on the control sequence and relay. So this system could control load more efficient and stable. Also the conventional load control circuit is not needed. Therefore, it is possible to improve the simple system configuration, which is resulted in cost effective and time saving. So this system is anticipated on time and coast.

• 대한전자공학회논문지TC
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• 제40권9호
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• pp.349-357
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• 2003

전력설비의 용량이 커지고 전력계통이 복잡해짐으로서 고품질과 안정적인 전력공급을 하기 위해 각 계층간에 연계되는 데이터를 에러 없이 처리하는 프로토콜을 요구하게 되었다. 그러나 서울(EMS)과 광주(RCC) 또는 RCC와 SCC에 사용하고 있는 HDLC나 TCP/IP 통신 프로토콜은 속도의 지연, 에러 발생 등으로 신뢰성을 감소시키고 있다. 이론 개선하기 위해, 본 논문에서는 ICCP 통신 프로토콜을 적용하여 전력 설비의 원거리 제어를 위한 전력 통신시스템을 구현하였다. 오류보정을 위해서 프로그램을 수정하였으며, BLT 최적 조건을 적용하여 구현하였다. 전력통신 시스템에 ICCP 프로토콜을 적용하였을 경우 HDLC와 TCP/IP 프로토콜을 적용한 경우보다 에러가 감소하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
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• pp.298-302
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• 2004

In this paper, AC electric vehicle propulsion system(Converter/Inverter) using high power semiconductor, UM(Intelligent Power module) is proposed. 2-Parallel operation of two PWM converter is adopted for increasing capacity of system and the VVVF inverter control is used a mixed control algorithm, where the vector control strategy at low speed region and slip-frequency control strategy at high speed region. The proposed propulsion system is verified by experimental results with a 1,350kW converter and 1,100kVA inverter with four 210kW traction motors.

• 한국산학기술학회논문지
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• 제10권9호
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• pp.2379-2383
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• 2009

본 논문에서는 발전설비를 관리하기 위한 RFID 기반의 정보화 시스템 구현에 관한 논문으로, 관리되는 상태 항목에는 자재의 입고 및 출고, 구매 발주, 도면 관리, 설비규격, 운용자 조작, 수주, 재고, 생산 실적, 시스템 관리 등이 있다. 제안된 논문은 발전설비 고장 상태 진단의 모니터링 서비스 제공을 목적으로 RFID 기반 상태 관리시스템을 설계 및 구현하였다.

• Journal of Power Electronics
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• 제12권4호
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• pp.654-663
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• 2012

In this paper, a digital control strategy based on equivalent fundamental and odd harmonic resonators is proposed for single-phase DVRs. By using a delay block, which can be equivalent to a bank of resonators, it rejects the fundamental and odd harmonic disturbances effectively. The structure of the single closed-loop control system consists of a delay block, a proportional gain and a set of zero phase notch filters. The principle of the controller design is discussed in detail to ensure the stability of the system. Both the supply voltage and the load current feedforwards are used to improve the response speed and the ability to eliminate disturbances. The proposed controller is simple in terms of its structure and implementation. It has good performances in harmonic compensation and dynamic response. Experimental results from a 2kW DVR prototype confirm the validity of the design procedure and the effectiveness of the control strategy.