• Journal of Electrical Engineering and Technology
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• 제3권4호
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• pp.520-527
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• 2008

This work focuses on the evaluation of active power filter which is controlled by fuzzy logic and neural network based controller for harmonic mitigation and power factor enhancement. The APF consists of a variable DC voltage source and a DC/AC inverter. The task of an APF is to make the line current waveform as close as possible to a sinusoid in phase with the line voltage by injecting the compensation current. The compensation current is estimated using adaptive neural network. Using the estimated current, the proposed APF is controlled using neural network and fuzzy logic. Computer simulations of the proposed APF are performed using MATLAB. The results show that the proposed techniques for the evaluation of APF can reduce the total harmonic distortion less than 3% and improve the power factor of the system to almost unity.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2276-2279
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• 2011

The AUTS(Advanced Urban Transit System) are developed by government R&D business. This units are under main line performance test in Daebul test line. Both AC and DC could apply to the AUTS for pantagraph voltage. So main transformer and some high voltage filters are added to the under-frame. As a result the total weight of each car(Mc1-Tp1-M-T-Tp2-Mc2) is different. And axle load is different each other. The main characteristics of AUTS(Advanced Urban Transit System) are as follows. One inverter control one motor, DDM(Dircet Drive Motor), no driving gear, plug no end door, self-steering bogie etc. These matters could be appeared to strange vibration. So vibration test is important. The vibration test performed to Mc1 and Tp1. The results were checked to the up-down direction and left-right direction for acceleration.

• 전기의세계
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• 제23권4호
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• pp.60-65
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• 1974

This paper is to study on the pilot work of bi-directional S.C.R. power converter adopted by the method of diode-bridge type circuit. This apparatus acts as a converter when it is used in convering 3-phase a.c source to d.c output, and it can be used as an inverter which recovering surplus d.c power to a.c source when d.c load become active to cause the induced voltage higher than the presetted point of d.c output voltage. At the same time, its d.c voltage varies continuously in the presetted range of positive and/or negative polarity. As a result of test, the AC/DC bi-directional power converter represents maximum converting efficiency of 91% and power factor of 0.98. Furthermore, this converter also can be applied as a cycleconverter by varying the period of gate triggering signal.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.62-63
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• 2011

The wireless power transfer system using electromagnetic resonance is consists of PFC circuit, LLC resonant converter, high frequency DC-AC inverter and ECR devices for wirelessly transmitting the power. The output voltage of the module with free input voltage is 1MHz, 230Vp-p. As a experimental result, the wireless power transmission is confirmed and it is varified the validity of the experiment.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.478_479
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• 2009

It is important to find the maximum efficient conditions for the output of the photovoltaic(PV) system to determine the optimal installation location of the PV system. The output of PV system depends on the irradiance. Therefore, this paper introduces the pilot experiment set to track the output of PV system according to the variance of irradiance and analyzes the result of experiment using this set. The pilot experiment set consists of the PV modules and the inverter to convert DC power to AC power. For this experiment, the fixed and tracked modules are used.

• 전기학회논문지P
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• 제54권1호
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• pp.15-19
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• 2005

This paper analyzed the power loss characteristics according to winding thickness and winding method of high frequency transformer. Power loss was analyzed by PExprt using FEM tool. The ferrite core model for analysis be used the EE10 type of TDK cop.. Transformer model objected flyback transformer type applied to flyback converter/inverter. Therefore, analysis results of loss were obtained from inner parameters of DC, AC resistance, leakage inductance, copper loss, core loss, and temperature etc.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2715-2720
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• 1999

To prevent the short circuit of upper and lower arms of bridge type PWM converters as like a voltage source inverter and PWM AC/DC converter, the dead time is inserted in between two switching signals. As a result, unexpected errors are occurred. In this paper, a new dead time minimization method is proposed. According to the proposed method, very short time which is equal to the applied dead time or more short than it, is adopted at the time of current polarity is changing. Moreover, it can be operated with the polarity information of reference current in case of current control. With the experimental results. the varidity of proposed method is verified.

• 태양에너지
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• 제18권1호
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• pp.19-25
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• 1998

This paper describes a design method and characteristics analysis of the 3 kW grid-connected photovoltaic power generation system to establish the basic application technology of photovoltaic systems. The design specification of a 3 kW photovoltaic power generation system including a DC/AC inverter is suggested to investigate the system performance for grid connection. The results of the demonstration test from February to October show that the system with utilization rate up to 17% has reliable operation characteristics and is useful for peak-shaving of utility power.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.727-732
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• 2000

This paper is on the development of a auxiliary power supply for the coach of Indian Railways. The auxiliary power supply system supplies the power for air-conditioners, air-compressors, lighting equipments, controllers, etc. It converts the input voltage, DC 110V which is supplied from battery, to AC 3${\Phi}$ 415V of 30kVA capacity. This is a low voltage-high current type converter system and largely consists of boost chopper and 3 phase inverter. Adopting a optimal control algorithm and simple power circuit, we realized the more reliable and competitive system for satisfaction of Indian Railway's strict requirement for vibration, temperature and dust. We completed the design, the manufacture and the field test of the system successfully and proved the system performance and reliability as a result of those tests.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 전력전자학술대회 논문집
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• pp.366-370
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• 1998

Indirect vector control for induction motors requires the use of observers for estimation or observation of rotor flux magnitude and position. In this paper, authors discribe the induction motor vector control and introduce a nonlinear observer, named ELO(extended Luenberger Observer), without simulation results as a preliminary work for trial application. Normally, design of nonlinear observer need coordinate transfromation and linearization through solving the partial different equation. However, ELO requires minimal solution of nonlinear partial differential equation. Simulation was performed by under the enviroment of Matlab and Simulink without the proposed observer because we are still working. Simulation was performed with conventional flux observer, a dc-ac inverter by SVPWM technique, a vector controller armed with multiple PI controllers