• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.115-115
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• 2010

This paper introduces a measurement system that measures behavior and electrical characteristics of overhead contact line irregular sections in real-time. For verification, we developed a prototype of the real-time overhead contact line irregular section behavior measurement system and a monitoring system for field tests. The current and temperature of contact wires and messenger wires were measured real-time by applying the system at KTX a commercial line. Therefore, acquiring data is possible with the developed system and this system that measures one of the fundamental and key factors, the catenary current, should be applicable to various areas such as detecting characteristics for designing overhead contact lines, enhancing speed, and enhancing energy.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.727-732
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• 2000

This paper is on the development of a auxiliary power supply for the coach of Indian Railways. The auxiliary power supply system supplies the power for air-conditioners, air-compressors, lighting equipments, controllers, etc. It converts the input voltage, DC 110V which is supplied from battery, to AC 3${\Phi}$ 415V of 30kVA capacity. This is a low voltage-high current type converter system and largely consists of boost chopper and 3 phase inverter. Adopting a optimal control algorithm and simple power circuit, we realized the more reliable and competitive system for satisfaction of Indian Railway's strict requirement for vibration, temperature and dust. We completed the design, the manufacture and the field test of the system successfully and proved the system performance and reliability as a result of those tests.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1878-1884
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• 2010

Currently in Korea, neutral sections in front of substations and sectioning posts are greatly divided into AC/DC sections and AC/AC sections. Considering catenary damage and safety issues trains pass crossover by coasting driving at notch-off. However in cases of Japan, China, or Taiwan, the usage of automatic crossover system makes it possible to pass at notch-on, enhancing high-speed railway operation for efficiency, and stability. These are the purposes of developing automatic power crossover system in neutral sections. This paper introduces two methods to detect the position of a train required to activate automatic crossover systems in neutral sections. The optimal method is expected in terms of the distance of neutral section.

• Railway Journal
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• v.18 no.1
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• pp.42-49
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• 2015

이상에서 살펴본 것과 같이 과거 몇 년간 미국 내에서의 자기부상열차 기술개발과 노선건설에 있어서 그렇다할 성과는 없었다. 국가적 차원에서의 대규모 기술개발 자금지원도 없었고 단지 기업이나 주정부로부터의 재원조달이 주였다고 할 수 있다. 다행이 일본이 Washington DC와 Baltimore 노선에 일본의 초전도 자기부상열차 기술과 5조 원의 자금을 투자하겠다고 나서 가시적인 결과가 기대된다. 도시형의 경우 Orlando에서 24km 노선건설을 위한 토지임대협상이 진행 중인데 금년 봄에 결론에 도달할 것으로 알려지고 있다. 그 이외에도 몇 개의 다른 지역에서 노선건설이 추진 중이어서 더 두고 볼 일이다. 연구비 확보에 있어서는 연방정부의 지원이 줄자 전통적인 공공자금에서 민간자본으로 눈을 돌리는 것도 최근의 경향이라고 할 수 있다. 마지막으로 저자가 미국의 기술개발 환경에서 배운 점 중의 하나는 독창적인 기술이 미성숙이라고 하도라도 공개적으로 제안하고 평가를 받으며 사회는 그에 대한 연구비를 지원한다는 것이다. 그 결과 새로운 개념의 자기부상기술의 다수는 미국에서 나오고 있다.

• Journal of the Korean Society for Railway
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• v.10 no.1 s.38
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• pp.51-56
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• 2007

In this paper, control schemes are developed for a propulsion system(Converter/Inverter) in electrical train. A robust controller for PWM converter is proposed. The converter controller consists of a PI controller for DC output voltage and a current controller using error-space approach for maintaining the sinusoidal current waveform and unity power factor. This proposed method is based on characteristic ratio assignment(CRA) method which has the advantage to design the optimal gain to meet the referenced response and overshoot within the limit range. Inverter system is controlled by vector control and slip frequency control. At low speed region, vector control scheme is applied to control instantaneous torque and slip frequency control is performed under overmodulation region and one pulse mode. Because output voltage of converter contains harmonics ripple at twice input ac line frequency, control scheme is developed to reduce the pulsating torque current. The performance of propulsion system will be verified by simulation and prototype experimental results.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.644-647
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• 1999

The main objective of this paper is to design and test a new type of polymer ZnO surge arrester for DC power system of railroad vehicles. The rated voltage is 1500v direct current. The main research works are focused on structure design by finite element method, rat ing vol tape, temporary over vol tape and studies of character int ice of polymeric surge arrester .

• Journal of the Korean Society for Railway
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• v.7 no.1
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• pp.1-8
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• 2004

A newly-built inverter has to undergo a series of stress tests in the final stage of production line. This can be achieved by connecting it to a dynamometer consisting of a three-phase machine joined by a rigid shaft to a DC load machine. The latter is controlled to create some specific load characteristic needed for the test. In this paper a test method is proposed, in which no mechanical equipment is needed. The suggested test stand consists only of a inverter to be tested and a simulator converter. Both devices are connected back-to-back on the AC-side via smoothing reactors. The simulator operates in real-time as an equivalent load circuit, so that the device under test will only notice the behaviour of a three-phase machine under consideration of the load. In oder to prove rightness of the suggested test method, the simulation and actural experiment carried out emulation for a 2.2kW induction motor.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.185-189
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• 2008

D.C. traction systems can cause stray currents which could adversely affect both the railway concerned and outside installations, when the return circuit is not sufficiently insulated versus earth. As experience for several decades has not shown evident corrosion effects from a.c. traction systems and actual investigations are not completed, stary currents flowing from a d.c. traction system is issued. D.C. traction systems can cause stray currents can be corrosion and subsequent damage of metallic structures, where stray currents leave the metallic structures. There is also the risk of overheating, arcing and fire and subsequent danger to persons and equipment. Any provision employed to control the effects of stray currents be checked, verified and validated. Direct measurement of stray current is difficult and a provision employed to control the effects of stray currents is proposed.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1979-1983
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• 2011

FRP(Fiber Reinforced Plastic) support insulators for DC(direct current) were developed and their electrical and mechanical characteristics were investigated. Electrical tests were carried out to measure flashover voltages under common use frequency condition. Tensile and bending tests were performed for the mechanical characteristics. The test results showed that FRP support insulators have superior voltage resistances and strengths to porcelain insulators. Field test also is carried out to measure adaptation and to compensate the defect. The test result showed that a new product has no defect in electrical and mechanical.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.50-54
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• 2016

본 논문에서는 전동차의 정차 시 발생하는 회생에너지를 Battery에 충전할 수 있는 전력 변환 장치를 제안한다. 제안된 전력 변환장치는 DC 1500~2000의 가선전압을 분압하여 저압스위칭 소자 적용하며, 고주파 절연 변압기를 적용하였다. 이를 통해 시스템의 스위칭 주파수를 상승시켜 수동 소자들의 사이즈 축소 및 비용 절감 효과를 높이고, 가선과 Battery의 전기적 절연으로 시스템의 안정성을 높였다. 또한 가선 전압 분압을 통해 입력 전압의 변화에 유동적으로 대응할 수 있으며, 시스템의 병렬 구성을 통해 용량의 확장성을 가지게 된다. 제안된 논문에서 제안된 회생에너지 전력 변환 장치는 20[kW] 회생 컨버터 모듈의 5직렬 구성을 통해 100[kW]급 회생 컨버터 유닛을 구성하였으며, 회생 컨버터 유닛을 5병렬로 구성하여 500[kW]급 회생 전력 변환시스템을 구성하였다. 제안된 회생에너지 시스템은 모의 가선 전압 장치 및 Battery 부하를 통해 시스템의 타당성을 검증 한다.