• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.358-361
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• 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 KSR Conference
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• 2000.11a
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• pp.720-726
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• 2000

The advance of traction motor control technology and the complexity of the traction power supply system makes the simulation essential in determining the dimension of the traction power supply system. The conventional method, use of the simplified and/or empirical equations, becomes inadequate in optimization of the design. The simulator presented in this paper is a numerical time based simulator running on a PC. The input to the simulator includes the track data, the train characteristic, network data and operating data. Basically the simulator conducts train running simulation and loadflow study repeatedly. The principle algorithms and its output is discussed in the paper.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.686-693
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• 2003

An intensive study was conducted for crashworthiness structural design of recently developed Korean High Speed Train. Two nam design concepts are setup to protect the both crews and passengers from serious injury at heavy collision accidents, and to reduce damages of the train itself at light collision accidents. For occupant protection a collision against a movable 15 tons rigid obstacle at 110 kph and a train-to-train collision at 30 kph were selected as accident scenarios for the heavy collisions based on the train accident investigations. A train-to-train collision at 8 kph was used for the light collisions. The crashworthiness behaviors of KHST have been evaluated numerically using the finite element method. Also, one-dimensional collision analyses show good crashworthy responses in a full rake consist and 3-dimensional shell element analyses do in the front-end structures of the power car. Occupant analyses and sled tests demonstrated that KHST performs well enough to protect occupants under the considered accident scenarios.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.51-53
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• 2005

At the railway feeding system, a role of dead section is very important. Because, dead section is essential installation that AC feeding system meets DC feeding system or phase is changed between AC feeding systems. But, in dead section it is possible that an electric train meets interruption. In Korea, a study on the dead section isn't yet accomplished in depth. Accordingly. In this paper, when electric train is in dead-section power quality problem on electric train was dealt. Modeling and simulation using PSCAD/EMTDC was accomplished to analyze.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.473-478
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• 2005

Active suspension system improves ride quality with optimized suspension force, generated by electric, hydrolic or pneumatic power and controlled by micro-processor under various operation condition of train, while Semi-Active susepsion system provides optimized and controlled characteristics of suspensions such as damping coefficient without external energy. The benefits fo Semi-Active suspension are no required power source and to be made compact with lower cost. Train with narrow gauge could be more unstable than one for normal or wide gauge, and it could be more vibrated than others one by external force such as aerodynamic force and track irregularity. So, the reduced ride quality could be improved with appling with Semi-active suspension system. In this report, the Semi-Active suspension system for narrow gauge train shall be proposed and to prepare the Roller Rig test of this train, integration of system, development of control algorithm and confirmation of its performance with simulation tool would be taken.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1643-1648
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• 2009

The braking system of train must posses the large baking effort in order to stop the train safety within the limited traveling distance. but, the excessive braking effort has been deteriorated the ride comfort due to high level of deceleration and jerk, and sometimes occurred the skid. because the applied braking force exceeds the allowable adhesive force. this skid causes not only to increase the a stopping distance but also to deteriorate the safety of train and damage the rall surface by wheel flat. In the present paper, braking force for disk brake of Tilting Train eXpress(TTX) was measured though on convention line test and the traction force was estimated by using the analytic model in skid condition. also, we have discussed the relationship between the bake force and traction force in starting condition.

• International Journal of Railway
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• v.6 no.1
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• pp.1-6
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• 2013

Electric railway system driving the electric cars using power from catenary has been secured by performance of stable tracking between pantograph and catenary. The performance of the power collecting of pantograph is the one of the most important skills for high-speed train speed. The first Korea high-speed train(KTX) is 20 cars in one train set. In the meantime, collecting capability of single pantograph collector at one train set was confirmed through evaluation of the performance and the stability test. However, more research is needed to build for a stable collecting capability of coupled Korea's KTX-II High-speed system which is developed in Korea. In this study, actual vehicle test of coupled KTXSanchon was made to analyzing the data presented by the dynamic nature of catenary and pantograph, and the interface characteristics.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.38-46
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• 2002

This paper evaluates crashworthiness of KHST carbodies under the SNCF accident scenario (collision against a movable rigid mass of 15 tons at 110 kph) and the scenario of train-to-train collision at 30 kph. The numerical results show that the final design of the KHST power-car doesn't have a good response on crashworthiness. So an improved design has been suggested for it. The improved design has shown good performances in the viewpoint of energy absorption and survival space at several numerical simulations, such as the accident collided against a deformable dump truck of 15 tons at 110 kph, the driver's dummy analysis, and the accident of train-to-train collision for the first three units at 30 kph.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.625-628
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• 1996

Recent power converting system for an electric train has characteristics of a complex electromechanical system, which includes VVVF inverter, bidirectional converter, ac motor and controller and etc. So in order to analysis its dynamic characteristics reliably, a powerful and flexible simulation technique is needed. Concerned with this respect, because the Simulink has a veriety of powerful functions and analysis tools not available in conventional power electronics simulation packages, it can be effectively applied to the simulation of the power converting system. In this paper, a schematically similar model for an electric train power converting system is derived on the Simulink Window, based on the Dynamic Node Technique, and several simulations have been implemented with the model. With the simulation results, the characteristics of the power converting system and the easeness of the proposed Simulink-based simulation technique could be verified clearly.

• ETRI Journal
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• v.33 no.5
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• pp.679-688
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• 2011

A new discrete-amplitude pulse width modulation (DAPWM) scheme for a high-efficiency linear power amplifier is proposed. A radio frequency (RF) input signal is divided into an envelope and a phase modulated carrier. The low-frequency envelope is modulated so that it can be represented by a pulse whose area is proportional to its amplitude. The modulated pulse has at least two different pulse amplitude levels in order that the duty ratios of the pulse are kept large for small input. Then, an RF pulse train is generated by mixing the modulated envelope with the phase modulated carrier. The RF pulse train is amplified by a switching-mode power amplifier, and the original RF input signal is restored by a band pass filter. Because duty ratios of the RF pulse train are kept large in spite of a small input envelope, the DAPWM technique can reduce loss from harmonic components. Furthermore, it reduces filtering efforts required to suppress harmonic components. Simulations show that the overall efficiency of the pulsed power amplifier with DAPWM is about 60.3% for a mobile WiMax signal. This is approximately a 73% increase compared to a pulsed power amplifier with PWM.