• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.1
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• pp.32-39
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• 2000

In this paper, an improved re-adhesion control scheme is proposed for 1C4M railway traction system. It is well known that the coefficient of adhesion between wheel and rail has a maximum value at a certain slip velocity. In the proposed scheme, adhesive effort is estimated by a full-order observer and the driving torque of motor is controlled to get maximum adhesive effort. The-adhesion control simulator is designed to verify the proposed re-adhesion control algorithm. The simulation results and experimental results are presented.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.89-90
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• 2016

경전철 차량에 위치한 집전장치는 무선급전 인버터로부터 전력을 공급받아 동력계통 또는 에너지 저장장치에 전력을 전달하는 역할을 한다. 따라서, 집전장치의 손실을 최소화 하고 전력을 안정적으로 전달할 수 있는 제어방법이 필요하다. 본 논문은 이러한 필요를 만족하는 적절한 제어방법을 제안한다. 시뮬레이션을 통하여 제안한 집전장치 제어방법의 유효성을 검증한다.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.316-320
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• 2008

A light rail transit, using a linear induction motor, is generally composed with reaction plates along railroad track and the three phase primary on the vehicle. This linear induction motor is driven to keep clearance between the primary and the secondary of the ground for preventing any contact. Therefore efficiency and power factor is very low. In addition, the reaction plate installed on the ground throughout entire railway is impossible to keep uniform gap and it may cause system deterioration. In this paper, A rotary-type small-scale model of a linear induction motor for various characteristic analysis is designed. Thrust force, normal force and input current of the model by air-gap variation have been analyzed by using a Finite Element Method (FEM). The effects of air-gap variation on system performance have been considered by analysis results.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1389-1396
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• 2008

There are many studies on the ride comfort for the train from the viewpoint of passenger. But there are only a few studies on the ride comfort for engineers in the locomotive. The railway has the track conditions, such as irregularities, rail joints, turnout, level crossing, transition curves and super-elevation ramps, which cause vibrations. Generally, the ride comfort for the train is evaluated by using the vibrations. In this study, vibration accelerations have been measured in the cabin rooms of locomotives, such as DL(Diesel-electric Locomotive), DHC(Diesel Hyduralic Car) and NEL(New-Electric Locomotive) when running on the Kyoungbu conventional line. And then, their ride comforts has been analyzed and evaluated by statistical method according to UIC 513R.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.12
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• pp.1735-1742
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• 2018

The number of electric railway failures will increase due to the external and internal effects of electric railroads. The grounding test with 25,000V is to artificially test the transmission voltage to ground, and it is possible to cause risks of electric shock and other equipment insulation damage in neighboring enclosure. In 2016, method of fault localization changed to low - voltage at 380V from artificially high- voltage in the grounding tests since opening of Seoul Metropolitan Express Railway; The method is more accurate and safer rather than the previous one because it gets more data from unlimited grounding tests. However, an electric current falls on the track section where the track branches and vehicle bases with many lines. To precisely detect a transitive phenomenon, it is necessary to continuously study and additionally install.

• Journal of the Korea Society of Computer and Information
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• v.23 no.12
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• pp.179-184
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• 2018

In this paper, we have proposed the development of DC-DC converter for LRT power supply. First of all, we have studied converter technology, main functions and characteristics were determined. In also, the converter design was carried out to meet the system design conditions. Based on this design, converter simulation is performed to enable stable charging and discharging of the vehicle system. We have performed the Light-load test according to charge mode, discharge mode. As a result, the manufactured converter performance was verified through the load test, and it's stability was confirmed.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.680-689
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• 2011

A dynamic analysis procedure is developed to provide a comprehensive estimation of the dynamic response spectrum for locomotive's wheels running over a Pre-Stressed Concrete (PSC) box girder bridge on the Korea high speed railway. The wheel force spectrum with the bridge behavior are analyzed as the dynamic procedure for various running speeds (50~450km/h). The high-speed railway locomotive (KTX) is used as 38-degree of freedom system. Three displacements(vertical, lateral, and longitudinal) and three rotational components (pitching, rolling, and yawing). For one car-body and two bogies as well as five movements except pitching rotation components for four wheel axes forces are considered in the 38-degree of freedom model. Three dimensional frame element is used to model of the PSC box girder bridges, simply supported span length of 40m. The irregulation of rail-way is derived using the exponential spectrum density function under assumption of twelve level tracks conditions based on the normal probability procedure. The dynamic responses of bridge passing through the railway locomotive with high-speed analyzed by Newmark-${\beta}$ method and Runge-Kutta method are compared and contrasted considering the developed models of bridge, track and locomotive comprehensively. The dynamic analyses of wheel forces by Runge-Kutta method which are able to analyze the forces with high frequency running on the bridge and ground rail-way are conducted. Additionally, wheel forces spectrum and three rotational components of vehicle body for three typical running speeds is also presented.

• Journal of the Korean Society for Railway
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• v.15 no.4
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• pp.334-342
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• 2012

It is connected with various gauges existing in Euro-Asian continents. Such differences impedes the operation seriously as on the contact of railway tracks of different gauge the cargo must be either transshipped or the running assemblies of rail vehicles must be exchanged. Those operations are costly, time-consuming and require extended infrastructure together with very expensive storage and transshipment facilities at border-crossing point. Moreover, those operations extend transportation time considerably. Therefore, effectiveness of railway transportation systems significantly depends on track gauge change 1435/1520mm, which connects with complicated handling-shifting operations. The paper concerns assessment of effectiveness in strategical rail systems with gauge changing. The paper presents short description of transport system with gauge changing and initial assessment of shifting technologies. Method of system assessment comparison based on Life Cycle Cost model is described here as well.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.4
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• pp.577-583
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• 2013

We have analyzed influence of potential rise in negative bus, which caused by decrease of power feeding line insulation, upon protecting method of DC ground protection device which detecting potential rise between negative bus and ground in order to detect ground fault in the rubber wheel system. For this purpose, we proposed negative potential equation between negative bus and ground and calculated negative potential according to system condition changes by estimating power feeding line insulation changes in steel wheel system and rubber wheel system, and equalizing DC power feeding system when ground fault occurred. Also, in order to estimate negative potential of real system, we modeled the rubber wheel system, and simulated normal status, grounding fault occurrence and power feeding line insulation changes. In normal status, negative potential did not rise significantly regardless of vehicle operation. When ground fault occurred, negative potential rose up over 300V regardless of fault resistance. However, we also observed that negative potential rose when power feeding line insulation dropped down under $1M{\Omega}$. In conclusion, our result shows that in case of rubber wheel system unlike steel wheel system, relay will be prevented maloperation and insulation status observation can be ensured when ground over voltage relay will be set 200V ~ 300V.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.1
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• pp.160-166
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• 2010

Railroad level crossing systems are used to prevent train from collisions by informing pedestrians and vehicles of approaching trains on the level crossing. The current detection systems mostly use track-based electrical circuits to detect approaching trains. The making and breaking of the circuit when the train wheel passes along the track sends a signal to barriers that restrict access to the track. Unfortunately, this track-based signal system is vulnerable to malfunctions in certain situations. If the rail becomes rusted due to moisture, weather conditions, or infrequent use, the electrical circuit detection system could fail. Such a failure could lead to a train-vehicle or train-pedestrian collision. This paper suggests a replacement of the electrical circuit-based system with an infrared detection system. The research shows that an infrared detection system improves safety by reducing the frequency of detection failure of the alarming circuit to system.