• Journal of Power Electronics
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• 제9권1호
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• pp.1-17
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• 2009

Permanent magnet brushless DC (PMBLDC) motors are the latest choice of researchers due to their high efficiency, silent operation, compact size, high reliability and low maintenance requirements. These motors are preferred for numerous applications; however, most of them require sensorless control of these motors. The operation of PMBLDC motors requires rotor-position sensing for controlling the winding currents. The sensorless control would need estimation of rotor position from the voltage and current signals, which are easily sensed. This paper presents state of the art PMBLDC motor drives with an emphasis on sensorless control of these motors.

• Journal of Power Electronics
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• 제12권5호
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• pp.842-850
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• 2012

Learning Power Electronics is essential in both electrical and electronic engineering fields and the introductory courses are similar in many universities. Taking this premise into account, an educational computer-aided platform for power electronics will be presented in this paper. This educational platform includes an e-book, a set of power electronics animations, Java simulations, as well as several hands-on training sessions. The main advantages of this platform are twofold. First, all necessary teaching tools are combined on a single platform. And secondly, access to this platform is available free of charge and with no complicated registration requirements. In addition to traditional teaching techniques, the use of this platform has demonstrated an increase in student participation and has consistently improved their academic performance. Data consist of surveys, which guarantee both reliability and validity through psychometric techniques.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2220-2222
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• 2005

Epoxy Insualtion spacers for supporting the conductors and partitioning the sections in $SF_6$ Gas insulated Switchgear(GIS), require higher electrical, Thermal and mechanical reliability with other principal components in GIS to be operated without any failure in use. In this paper, we describe the results of the performance evaluation of electrical and mechanical properties for extra high-voltage GIS according to KEPCO spec. and the requirements of the insulators for GIS specified by IEC 62271-203(2004).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전력기술부문
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• pp.275-277
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• 2003

This paper deals with Object-oriented Database(OODB) which is designed for power system analysis, and describes load flow analysis using OODB. Database management systems are widely used and achieve high reliability of data management in the engineering fields. However conventional database systems, relational database system, have disadvantages in application to power system analysis. This paper presents advantages of OODB for modeling complex data of a power system analysis. The OODB supports data modeling requirements of GUI applications and the performance is well acceptable for GUI applications.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 A
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• pp.152-155
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• 1993

Protective Relay in power system play a prominent part in minimizing power delivery interruptions and help to get a fast and secure restoration when a failure occurs. In order to meet the higher functional requirements in power system, the performance tests on response characteristic of protective relay is essential to ensure reliability. The purpose of this study is as follows: In order to evaluate performance of protective relay, it is intended to develop performance of digital protective relay simulator which is composed of digital protective relay part, behaviour analysis part, waveform generation part and simulation program to simulate pour system in detail.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.383-386
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• 2000

Fuse mounted elbow connector used for pad mounted transformer was designed and investigated. Requirements of electrical ratings such as partial discharge, ac withstand voltage and impulse voltage and material properties were proposed in accordance with IEEE 386 and pre-standard (PS) 147-219∼229 of KEPCO. The connector can be jointed with pad mounted transformer and current limiting fuse which is installed inside of the connector easily replaced with new one in the case of breakdown of the fuse. Electric field analysis was also introduced in other to verify the reliability of the design.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 전력전자학술대회 논문집
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• pp.634-637
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• 2001

The proposed contactless charger employs a pair of neighboring printed circuit board windings as a contactless energy transfer device, thereby making it amenable to low-profile designs and suitable for applications to the portable telecommunication/computing electronics in which stringent requirements for height, space, and reliability have to be met. The performance of the proposed charger is confirmed with experiments on a prototype charger developed for cellular phones.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.498-500
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• 2012

According to the climatic characteristics of the wind power output is difficult to predict and a severe strain due to a change in output has been very influential in the grid. Jeju Hangwon wind farm, many of the wind generator is installed in a wide area because it is not have this device that artificially Smoothing is needed. In addition, By the requirements of the power company active power supply / control and improve power system reliability and energy storage during the peak demand for electricity using the energy stored in the power supply is needed. In this paper, Unit 12 in Jeju Hangwon demonstrated 0.5MW PCS and energy storage system associated with the wind through the stabilization of output and the leveling of output and test results will be introduced.

• Journal of Electrical Engineering and Technology
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• 제11권4호
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• pp.860-868
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• 2016

A bidirectional DC-DC converter (BDC) is an indispensable electrical unit for the electric vehicles (EVs). High efficiency, high power density, isolation, light weight and reliability are all essential requirements for BDC. In this paper, a 3 kW BDC for the battery charger of EVs is proposed. The proposed converter consists of a half-bridge structure on the primary side and an isolation transformer and a synchronous rectifier structure on the secondary side. With this topology, minimum number of switching devices are required for bidirectional power flow between the two dc buses of EVs. The easy implementation of the synchronous rectification gives advantages in terms of efficiency, cost and flexibility. The proposed BDC achieves high efficiency when operating in both modes (step-up and step-down). A 3 kW prototype is implemented to verify theoretical analysis and the performance of the proposed converter.

• Korean Journal of Hydrosciences
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• 제5권
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• pp.57-70
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• 1994

For the system benefit optimization by considering risk or reliability from a multiple reservoir system using the Monte Carlo Technique, Many stochastically generated inflow series have to be used for the system analysis. In this study, the stochastically generated inflow series for the multiple reservoir system operation are preprocessed according to the considering system objectives and operating time periods. Through this procedure, several representative inflow series which have discrate probability levels and operation horizons are selected among the thousands of generated inflows. Then a deterministic optimization technique is applied to the hydropower energy estimation from the Han River Reservoir System which considers five reservoirs in this study. It took much less computational requirements than using the original Morite Carlo Technique, even though estimated result was almost similar.