• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.2210-2211
• /
• 2011

Load capacity varies according to a day of the week in traction power supply system, because time schedule in railway is changed as demand for passengers and freights. Therefore, Voltage drop also varies as load capacity. In Korea railway, Voltage collected from catenary in train is decreased, as load supplied traction power supply system is increased. Therefore, investigation about voltage drop should be performed, before development of countermeasure against voltage drop. The investigation can be performed by simulation or field test. Naturally, field test is more precise than simulation. In addition, field test should be carried out at peak load. This paper presents test and analysis about voltage drop in railway. The test is performed in both a day of the week and weekend. The analysis is figured out comparison load capacity between two days and voltage drop across terminal.

• Proceedings of the KSR Conference
• /
• 2004.06a
• /
• pp.1410-1412
• /
• 2004

Light flickering is caused by the degradation of power quality in electric train and can be measured by electronic illuminometer. This paper has shown the relations between voltage variations and illumination of lamps which has two kinds of incandescent lamp and 3-wavelength fluorescent lamp.

• Proceedings of the KIPE Conference
• /
• 1999.07a
• /
• pp.358-361
• /
• 1999

In auxiliary block of high speed train power factor correction and harmonics reduction is very important issue for efficient energy transport. The GTO-equipped PWM converter is used for traction untill resently. But the rising power capability of IGBTs resently allows to build IGBT-equipped PWM converter with a considerably increased switching frequency. This paper presents switching pattern, control method, operation mode and tuned filter to reduce dc link voltage ripple for paralleled converter.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 1999.11a
• /
• pp.162-167
• /
• 1999

In Auxiliary block of High speed train Power factor correction and Harmonics reduction is very important issue for efficient energy transport. The GTO-equipped PWM converter is used for traction untill resently. but the rising power capability of IGBTs resently allows to build IGBT-equipped PWM converter with a considerably increases switching frequency. In this paper presents switching pattern, control method, operation mode and tuned filter to reduce dc link voltage ripple for paralleled converter.

• Proceedings of the KSR Conference
• /
• 1998.11a
• /
• pp.296-301
• /
• 1998

Pentagraphs are used to supply electric power to train via trolley lines. The higher train speed is, the higher voltage and current levels 8u. Since electric power is supplied with slinding contact, localized abrasion is inevitable. It is difficult and dangerous to measure their shape manually. Measurement system of pentagraph slider with ultrasonic processing has been reported. In this paper, measurement system with image processing is proposed. The system consists of CCD cameras, image grabber board, and PC operated on Windows'95. Image processing algorithms are presented and some results are illustrated.

• Proceedings of the KSR Conference
• /
• 2006.05b
• /
• pp.850-855
• /
• 2006

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.553-558
• /
• 2003

The boundary estimation problem is used to estimate the shape of organic depend on the phase of the cardiac cycle or interested in the detection of the location and size of anomalies with resistivity values different from the background tissues such as nuclear reactor. And we can use the method to solve the optimal solution such as modified Newton raphson, kalman filter, extended kalman filter, etc. But, this method consumes much time and is sensitive to the initial value and noise in the estimation of the unknown shape. In the paper, we propose that multi-layer neural networks estimate the boundary of the unknown object using Fourier coefficient. This method can be used at the real time estimation and have strong characteristics at the noise and initial value. It uses voltage change; difference the homogeneous voltage to the non-homogeneous voltage, and change of Fourier coefficient change to train multi-layer neural network. After train, we can have real time estimation using this method.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.53 no.11
• /
• pp.589-595
• /
• 2004

This paper presents a modeling and simulation of a grid-connected wind turbine generation system with respect to wind variations, starting of large induction motor and three-phase fault in the system, and investigates voltage variations of the system for disturbances. It describes the modeling of the wind turbine system including the drive train model, induction generator model, and grid-interface model on MATLAB/Simulink. The simulation results show the variation of the generator torque, the generator rotor speed, the pitch angle, terminal voltage, system voltage, fault current, and real/reactive power output, etc. Case studies demonstrate that the pitch angle control is carried out to achieve maximum power extraction for wind speed variations, starting of a large induction motor causes a voltage sag due to a large starting current, and a fault on the system influences on the output of the wind turbine generator.

• Proceedings of the KIEE Conference
• /
• 2006.04a
• /
• pp.282-284
• /
• 2006

UV lamp systems have been used for cleaning of display pannels of TFT LCD or Plasma Display Pannel (PDP). However, the needs for high efficient cleaning and low cost made high voltage plasma cleaning techniques be developed and improved. In this paper, 3kW high voltage plasma power supply system was developed for LCD cleaning. The 3-phase input voltage is rectified and then inverter system is used to make a high frequency pulse train, which is rectified after passing through a high-power transformer. Finally, bi-directional high voltage pulse switching circuits are used to generate the high voltage plasma.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.5
• /
• pp.902-910
• /
• 2016

This paper presents the overall measurement system for on-line test of super-speed maglev train. The super-speed maglev train is composed of vehicle, propulsion, power, and so on. In order to evaluate and diagnose for sub-system, we made overall measurement system. Just like the other measurement system, it is designed to distributed type. The hardware is consist of SCXI, PXI, Terminal, UPS, and so forth. It is installed on a train, control room, power room and track to collect lots of signals. The software controls hardware system, monitors main data such as inverter current, converter voltage. Using the measurement system, we evaluated a lot of performances for vehicle, track, and so forth. Through the developed system have improved reliability and safety for super-speed maglev train.