• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.314-315
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• 2011

This paper introduces the design and control method of braking chopper circuit which can supply input power to ventilation inverter of traction control system. The DC input voltage from auxiliary block (static inverter) is normally used as an input of ventilation inverter. It converts DC input to AC output voltage to drive cooling fans for traction control system and traction motors. The electrical braking force is very important for high speed train to guarantee safety even though the train is running in the dead section where the pantograph voltage is not supplied. When the high speed train decelerate speed in dead section, the regenerative energy is dissipated by braking resistor. This paper proposed the braking chopper control method to implement rheostatic braking function and the appropriate chopper circuit for supplying voltage source to ventilation inverter during rheostatic braking mode. The proposed chopper circuit makes it possible for traction control system to regenerate power continuously regardless of the existence of pantograph voltage. The feasibility of proposed braking chopper control and circuit were proven by inertia load test and actual train field test.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.173-179
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• 2009

High-speed railway is important transportation in the world because it has a lot of merits like as very comfortable, environmental benefits, energy savings, etc. The increase of demand for high-speed railway influence to develop of new hish-speed trains. Many countries introduced new high-speed train in the market and it meets to the market's needs. They adopt new technology and systems like that active suspension, synchronous permanent magnetic motor, distributed drive system, aero acoustics, etc. In Korea, the project for R&D of new high-speed train is launched in 2007. We need analysis for main properties of new high-speed train(HEMU-400x). This paper presents the comparisons, analyzed characteristics of main properties like as traction system and braking system. In this analysis, we can know our technical position in the world and what is important to focus on the development. It is very useful to develop a next generation high-speed train in Korea.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.11
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• pp.1187-1192
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• 2013

In the case of 4 wheel drive (4-WD) type car, power switching occurs to 4-WD by operating lever or switch that operates power switching device attached in transfer case which can operate motor by electric signal. So if the RPM of motor is high, power switching will not exactly occur and can cause damage to gear in transfer case according to circumstances. So in this study, we applied 2 level of planet gear type motor spindle of motor drive part of a power train. And conducted decelerating to increase torque to switch power safe and accurately. Also, we researched efficiency of gear by designing reduction gear ratio and gear type and by calculating contact stress and bending strength. Based on researched content, we made drive head of power switching device and a reduction module which uses type that uses motor spindle as sun gear and ring gear as cover.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.3
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• pp.293-301
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• 2021

LTV(Light Tactical Vehicle) operating in our military requires higher levels of performance and durability to withstand harsher conditions than general vehicles, as they must travel on both rough-train and off-road as well as on public roads. Recently, LTV development is demanded a variety of test evaluations in order to satisfy ROC (Required Operational Capability) by the military requirement. However, there is no informations of driving test course for satisfying the durability performance of Korean tactical vehicle. Therefore, this study aims to provide basic data to establish reliable drive test conditions by analyzing the main maneuvering test site at the domestic and foreign country in order to select the representative drive course. These studies will provide a more scientific and systematic evaluation solution for the development of tactical vehicles, and can be effectively used to establish a certified system for military vehicle test evaluation in the future

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.6
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• pp.567-573
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• 2017

The drive shaft of passenger vehicle has an important role in transmitting the torque between the power train system and the wheels. Torsional fatigue failures occur generally in the connection parts of the spline edge of the drive shaft, when there is significant fatigue damage under repeated twisting loads. A heat treatment, an induction hardening process, has been adopted to increase the torsional strength as well as the fatigue life of the drive shaft. However, it is still unclear how the extension of the induction hardening process in a used material relates to its shear-strain fatigue life range. In this study, a shear-strain controlled torsional-fatigue test with a specially designed specimen was conducted by an electro-dynamic torsional fatigue test machine. A finite element analysis of the drive shaft was carried out using the results obtained by the fatigue experiment. The estimated fatigue life was verified through a twisting load test of the real drive shaft in a test rig.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.532-542
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• 2018

Because maglev trains have a propulsion and absorption force without contact with the rails, they can drive safely at high-speed with little oscillation. Recently, test model of a maglev propulsion train was produced and operated, and has since been chosen as a national growth industry in South Korea; there have been many studies and considerable investment in these fields. This study examined the dynamic responses due to bridge-maglev train interaction and basic material to design bridges for maglev trains travelling at high-speed. Depending on the major factors affecting the dynamic effects, the scope of this study was restricted to the relationship between dynamic responses. A concrete box girder was chosen as a bridge model and injured train and rail types in domestic production were selected as the moving train load and guideway analysis model, respectively. From the analysis results, the natural frequency of a bridge for a maglev train, which has a deflection limit L/2000, was higher than those of bridges for general trains. The dynamic responses of the girder of the bridge for a maglev train showed a substantial increase in proportion to the velocities of the moving train like other general bridge cases. Maximum dynamic response of the girder is shown at a moving velocity of 240km/h and increased with increasing moving velocity of train. These results can be used to design a bridge for maglev propulsion trains and provide the basic data to confirm the validity and verification of the design code.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.1
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• pp.40-47
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• 2002

This paper describes a re-adhesion control method for the Korean High-Speed Train (KHST) with parallel induction motor drive. To keep a traction efficiency and to improve vehicle maintenance, the adhesion characteristics between wheel and rail are analyzed. Also the re-adhesion controller is designed as the subsystem of induction motor vector control. In order to verify performance of the proposed control techniques, the simulation is executed by train model and a downscaled re-adhesion control simulator is utilized. Both simulation and running test results show that good re-adhesion characteristics are obtained.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.325-329
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• 2002

This paper is intended as an investigation of the interface between Neutral section insulators and pantograph interface. Neutral section insulators are installed at the boundary between AC catenary system and DC catenary system, which should provide electrical insolation between two different catenary systems and pass the trains without interruption. As the number of the pantographs installed on the train increased, which is necessary for the VVVF inverter drive trains introduced in recent years, there occurs an serious aspects of the interaction between pantographs and Neutral section insulators. These effects hinder the automatic switch operation of MCB(Main Circuit Breaker) after passing through the section insulators, and lead to the extra-ordinary wear of FRP insulator material of section insulators. Countermeasures in terms of the interface between the Neutral secton insulators and electric collection system of train are provided too.

• Journal of the Korean Society for Railway
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• v.6 no.1
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• pp.1-9
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• 2003

This article proposes an integrated systems engineering and safety analysis model for safety-critical systems development. A methodology in system design for safety is considered during the early phase of the development life cycle of systems engineering process. The evolution of the design automation technology has enabled engineers to perform the model-based systems engineering. A Computer-Aided Systems Engineering(CASE) tool, CORE, is utilized to integrate the systems engineering model with a system safety analysis model. The results of the functional analysis phase can drive the analysis of the system safety. An example of Communications-Based Train Control(CBTC) system for an Automated Guided Transit(AGT) system demonstrated an application of the integrated model.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.187-193
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• 1998

An inverter-driven induction motor is used as the traction motor for a high speed drive system that required safty, reliability and performance and so on. rotor bar and end ring of the traction motor are the electrical equipments which form the conductive close loop and then induce current by interaction wi th the current of stator. the materials selection of rotor bar and end ring are seriously considered in the aspects of electrical and mechanical specification and Motor slip relation to inverter. Particularly motor slip guarantee the safty and reliability of induction motor. this paper show the material selection and the determining of slip in the design of traction motor for high speed train by analyzing the specifications of material being used currently.