• Proceedings of the KSR Conference
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.918-923
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• 2011

On AC railway systems, the neutral sections are installed in front of substations and sectioning posts in order to avoid crash between power that have differing phases. In case railway vehicles pass through these neutral sections, it is necessary for them to switch to coasting driving by notch-off. This may reduce speed of the vehicles, resulting lowered train operation efficiency. The usage of automatic power switching systems makes it possible to pass neutral sections at notch-on, enhancing operation efficiency so that it is appropriate for high-speed railway applications. This paper introduces a simulator that assesses efficiency of automatic power switching systems in neutral sections. The is composed of a power supply system, electric railway vehicles, thyristor switches, and traction motors.

• Proceedings of the KIPE Conference
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• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
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• pp.298-302
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• 2004

In this paper, AC electric vehicle propulsion system(Converter/Inverter) using high power semiconductor, UM(Intelligent Power module) is proposed. 2-Parallel operation of two PWM converter is adopted for increasing capacity of system and the VVVF inverter control is used a mixed control algorithm, where the vector control strategy at low speed region and slip-frequency control strategy at high speed region. The proposed propulsion system is verified by experimental results with a 1,350kW converter and 1,100kVA inverter with four 210kW traction motors.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2203-2206
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• 2005

A load flow and short circuit fault simulation of AC electrified railway distribution systems is presented with DIgSILENT PowerFactory software. Load flow of electrified railways distribution system with concerning multi train lines and dynamic characteristics of train load is studied for different time laps. The dynamic characteristics of train load in starting and braking conditions with different starting and stopping times and its moving positions makes the load flow complicated so there is a great need in studying the effects of electrified railways on load flow. Short circuit fault transients is also studied and simulated for both power system or traction distribution system and their effects on the operation of the train sets is investigated.

• Proceedings of the KSR Conference
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1473-1478
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• 2007

In the respect of energy saving and reusing, it is necessary to reduce greenhouse gases emission and to enhance the operation efficiency in electric railway system. Recently, as the power electronics technologies are advanced, some countries have focused on the regenerative inverter to use regeneration energy on each line. When the electric tractions are stopped or slowed down, it is useful to supply the surplus energy to the power source by regenerative system, which increases its energy efficiency. Also, the generated energy can be supply to other tractions or equipments inside traction. Thus, it may help reduce construction cost of additional power plants. The purpose of this study is to describe the development status of the regenerative inverter system which suppress extra DC-line voltage and regenerate the energy instead of using a resister.

• Proceedings of the KIPE Conference
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.576-580
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• 2000

This paper describes about the field test of IGBT VVVF inverter for the propulsion system. The 1650kV class IGBT VVVF inverter has been developed. Therefore the field test is performed in SMG 6 Line to confirm its the reliability and performance. The train consists of 4M4T and the electrical equipment for field test are as follows : VVVF inverter 4 sets 16 traction motors and 3 SIVs The propulsion system which have the excellent acceleration/deceleration and the jerk chracteristics as well as starting ability on slope are taken through the field test.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제61권8호
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• pp.1210-1215
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• 2012

Traction motors for driving and power conversion devices using semiconductor switch are equipped with a transportation systems such as an electrical railway system. Power conversion devices have the possibility of malfunction by external electromagnetic waves. As a result, these could affect the safe operation of the railway. Moreover, the electromagnetic waves above safe limits will be harmful to the passengers inside the railway vehicles or anyone working around the rail-track. For this reason, the importance and need about the reliability check and complement of electromagnetic waves generated from the IPT(Inductive Power Transfer) system have been suggested for the safe application of the IPT system to the railway system. In this study, prediction for the electromagnetic wave properties was conducted through FEM(Finite Element Method) analysis of 5kW-class IPT system design model. Next, the 5kW IPT system prototype was made and then the small-scaled railway vehicle was made to mount the IPT system and the energy management system. Finally, the electromagnetic waves generated from the real small-scaled IPT system were measured and analyzed, and then the reliability check of predictions by FEM analysis were carried out.

• Proceedings of the KIPE Conference
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.196-198
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• 2007

In the substations for traction systems and the large-scale discharging system of secondary batteries, the voltage of DC bus line goes up by the regenerated energy and the energy is usually wasted in resistor for system stability. This paper proposes the DC power regenerating system using a three phase PWM inverter. The proposed system can regenerate the excessive DC power from DC bus line to AC supply and control the power factor of AC supply to unity. To implement unity power factor, the magnitude of the inverter output voltage should be higher than that of AC supply and therefore SVPWM technique is adopted. Computer simulations are carried out to verify the validity of the proposed system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• 제24권8호
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• pp.70-77
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• 2010

This paper presents the current and speed controller design procedure and their performance for the IPMSM based next generation high speed railway traction system. The next generation high speed railway system is a power distributed type and uses vector control method for a motor speed control. Since the speed and current controller gains of the vector control system directly affects to the transient characteristics and speed control capability, the systematic design of the controllers are required. In this paper the controllers are designed using the IPMSM based next generation high speed railway system parameters. Simulation programs based on Matlab/Simulink is developed. Finally the controller characteristics are analyzed by the simulation results.

• Proceedings of the KIEE Conference
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• 대한전기학회 2007년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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• pp.208-209
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• 2007

The measurement system is composed of the industrial computers installed in the console and the measurement racks mounted on each car. It is utilized to accumulate the data by the communication card and the optical cable. The optical cable and power cable are coupled at the connector located in joint of train to make easy to disconnect car each other. The signal conditioner is designed to choose and to extend the channel for each sensor readily, In this study, the programs for measurement and analysis were also developed to understand the traction system characteristics of TTX. Using this measurement system, we studied that acceleration test, re-powering test and gradually powering test. From the test results, we saw the performances of the traction systems are normal.

• Proceedings of the KSR Conference
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1221-1226
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• 2008

Present, the cooling method of using a phase-change heat transfer such as immersed type, heat pipe etc is applied in cooling of high-capacity power semiconductors of the main power system for the high speed train with the concentrated traction. In order to apply these phase-change cooling system to the high speed EMU to be developed, needed are technological researches of consideration of installing space, air passage, light weight material and miniaturization. Although this research establishes design specifications through theoretical analysis and computational analysis from the basic design process of the cooling system of the propulsion system for the high-speed EMU, when details design is completed, present improvement subject and optimum design before manufacturing the prototype of the cooling system on the basis of analysis results. And then, carried out will be the performance tests through prototype manufacture and reliability estimation by components of cooling system.