• Proceedings of the KSR Conference
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• 2011.10a
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• pp.754-760
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• 2011

In the DC traction system, a large load current of electric railcar leads to a voltage drop when a vehicle starts, and the regenerative power generated by brake system increases the catenary voltage. To minimize the voltage fluctuation during the train operation and make use of the regenerative power, several types of energy storage systems are being studied. The energy storage system that is being recently introduced consists of the supercapacitors for energy storage and the bi-direction DC/DC converter for charge/discharge control. The efficiency of the energy storage system depends on the train operation pattern. In this paper, the operation efficiency of the energy storage system was quantitatively analyzed via simulation study taking consideration of the train operation patterns. The simulation was conducted changing the headway of trains with the energy storage system that uses the bi-direction DC/DC converter and supercapacitor. The simulation results showed that the operation efficiency of the energy storage system increases as the headway increase.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2705-2710
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• 2011

With the rapid development of information and communication technology, CBTC system based on the wireless communication is widely applied in the railway signal system recently. CBTC system has advantages of lower installation space and maintenance fee than existing systems and the increase of transportation capacity and improvement of operating efficiency etc. due to the short headway. Based on the continuous wireless data communication between onboard and wayside equipment, CBTC system not only locates the train and transmits the information required for the train control, but also implements the moving block function by calculating the brake curves continuously according to distance from the preceding train. CBTC system can use either inductive loop (IL-CBTC) or radio frequency transmissions (RF-CBTC). In this paper, we propose RF-CBTC system architecture based on the functional modules, in which the CAN bus network is applied for the interfaces between the modules.

• KSTLE International Journal
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• v.1 no.2
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• pp.95-100
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• 2000

The thermal behaviors of disk-pad braking models has been analyzed for a high-speed train brake system using the coupled thermal-mechanical analysis technique. The temperature distribution, thermal distortion, and contact stress in the disk-pads contact model have been investigated as functions of the convective heat transfer rate. The FEM results indicate that multiple spot type pads show more stabilized thermal characteristics compared with those of the flat type pads for the increased convective heat transfer rate. The maximum contact stress for a friction pad loaded against a rubbing disk was occurred on the edge of the pad at the disk-pad interface.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2745-2747
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• 1999

Recently, the eddy current braking system has an advantage as the high speed railway train is developed. Because it is independent on wheel-rail coefficient of adhesion and it can be used in adverse weather conditions by reason of non-acting on wheels. In this paper we designed down-scaled eddy current brake model and developed control algorithm to generate constant braking torque. Our algorithm is verified through experiments to generate constant torque.

• Tribology and Lubricants
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• v.14 no.4
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• pp.29-36
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• 1998

The thermal characteristics of a disk such as temperature distribution, thermal behaviors and thermal stress during a braking operation has been analyzed for a high-speed brake using the finite element method. The maximum stress for a pad loaded against a disk was occurred at the trailing and leading edges of the disk pad at the underlayer-backplate interface. The FEM results indicate that the thermal characteristics of the spot type pad shows good performance compared with those of the flat type pad. Thus, the spot type pad in brake system may be recommended for the high-speed train system.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.103-108
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• 2005

Since the braking system of rolling stock is directly linked to it's safety, ensuring reliability of braking system and evaluation of performance of it are very important. To develope the performance of braking system, it is required advanced technology and gradually various factors in the field test result. This study is designed to analyze the air pressure control about braking force in rolling stock, also, by comparing braking force of KTX with that of high speed train. This paper suggests to establish a method of computation of braking force form the air pressure control. And The high speed train researches into patterns of braking system such as the train of speed up and introduction of electric and pneumatic braking system.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.139-144
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• 2004

Since the braking system of rolling stock is directly linked to it's safety, ensuring reliability of braking system and evaluation of performance of it are very important. To develope the performance of braking system, it is required advanced technology and gradually various factors in the field test result This study is designed to analyze various factors about braking force in rolling stock, also, by comparing braking force of KTX with that of high speed train. The study suggests to establish a method of computation of braking force suitable for high speed train having a lot of trouble in calculating braking distance by diversification of patterns of braking system such as the train of speed up and introduction of electric and pneumatic braking system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.1
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• pp.85-90
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• 2011

To maintain the safety and efficiency of railroad vehicles, it is important to understand the working of the brake system with anti-skid control unit (ASCU) for rolling stocks. In this paper, a HILS (Hardware In-the Loop Simulations) system with ASCU hardware (for logic) and a DSP board (for dynamics) is developed to analyze skidding of the Hanvit-200 train during the process of braking. Experimental results are presented for the case that the skid on one of the four wheels is artificially generated using a Simulink model. A convenient GUI is prepared using ControlDesk of dSPACE.

• Journal of the Korean Society for Railway
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• v.9 no.6 s.37
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• pp.677-681
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• 2006

In general, the braking system of high speed train has an important role for the safety of the train. To stop the train safely at its pre-decided position, it is necessary to combine the various brakes properly. The Korean high speed train (HSR-350x) has adopted a combined electrical and mechanical (friction) braking system. In this study, the measuring method that can obtain the disc braking forces and friction coefficient between disc and pad during on-line test of HSR-350x has been suggested and verified through the comparison of the results obtained from this method and those of the results of the dynamo-tests.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.146-154
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• 1999

The test facility of the 1/60-scale models for the train-tunnel interactions was recently developed to investigate the effects of entry portal shapes, flood shapes and air-shafts for reducing the micro-pressure waves radiating to the surroundings of the tunnel exits by KRRI in Korea. The launching system of train model was chosen as air-gun type. In present test rig, after train model is launched, the blast wave by the driver did not enter to inside of the tunnel model. The train model is guided on the one-wire system from air-gun driver to the brake parts of test facility end. Some cases of the experiments were compared with numerical simulations to prove the test facility.