• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.117-119
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• 2018

현대 사회의 시스템들은 점점 소형화 경량화 되어 가며, 공간적 제약을 받게 되었다. 최근 차량, 선박, 철도 등 제약적 공간이내에 많은 공간 확보를 통해 승차자의 쾌적한 환경 조성 및 다량의 물자를 운송하는 것을 목표로 각 시스템에 대한 소형화 연구가 활발히 진행되고 있다. 본 논문에서는 기존 Si 소자를 SiC 소자로 변경함으로써 얻을 수 있는 체적 및 손실 측면에서의 특성을 분석 및 장단점을 비교하였다.

• Proceedings of the KIEE Conference
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• summer
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• pp.1313-1315
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• 2004

고속철도는 수많은 하이테크 기술의 결정체이며, 이 중에서도 주변압기, 주전력변환장치 및 주전동기는 차량의 성능을 결정하는 매우 중요한 요소이다. 이러한 전장품들에 대한 다양한 성능을 평가하고 진단하기 위해 상시계측시스템을 구축하여 활용하고 있다. 이러한 계측장비들은 여러 전장품에 대한 계측 및 분석을 통한 시험평가와 동시에 완성차시험이나 본선시운전 시험시에 발생할 수 있는 고장원인을 찾아내고 해결하는데 많은 도움을 주고 있다. 본 논문에서는 상시계측시스템을 통해 주변압기, 주전력변환장치, 전동기 등에 대한 고장진단을 실시한 내용에 대하여 연구하였다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.1
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• pp.28-42
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• 2013

Personal Rapid Transit(PRT) is a new unmanned transportation system using electricity. The purpose of the PRT is relieving the congestion of city traffic and connecting between inner city and airport, high-speed railroad. PRT requires to develop devices for the guarantee of safety and reliability. PRT as the mean of rail transportation must be equipped with control system for front rail sensing. Ultra Wide Band(UWB) radar system is suitable for PRT's detection because it has the advantage of low power consumption, low interference and high resolution. In this paper, an improved adaptive Constant False Alarm Rate(CFAR) algorithm is proposed and studied in various noise environments. The proposed algorithm improves performance in various noise environments compared to the Mean Level CFAR algorithms and other adaptive CFAR algorithms.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.1-9
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• 2016

Railroad bridges account for 25% of the entire high-speed rail network. Railway bridges are subject to gradual structural degradation or fatigue accumulation due to consistent and repeating excitation by fast moving trains. Wireless sensing technology has opened up a new avenue for bridge health monitoring owing to its low-cost, high fidelity, and multiple sensing capability. On the other hand, measuring the transient response during train passage is quite challenging that the current wireless sensor system cannot be applied due to the intrinsic time delay of the sensor network. Therefore, this paper presents a framework for monitoring such transient responses with wireless sensing systems using 1) real-time excessive vibration monitoring through ultra-low-power MEMS accelerometers, and 2) post-event time synchronization scheme. The ultra-low power accelerometer continuously monitors the vibration and trigger network when excessive vibrations are detected. The entire network of wireless smart sensors starts sensing through triggering and the post-event time synchronization is conducted to compensate for the time error on the measured responses. The results of this study highlight the potential of detecting the impact load and triggering the entire network, as well as the effectiveness of the post-event time synchronized scheme for compensating for the time error. A numerical and experimental study was carried out to validate the proposed sensing hardware and time synchronization method.

• Journal of the Korean Society for Railway
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• v.10 no.6
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• pp.692-700
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• 2007

A trial run of locally-developed tilting train has been in process on Chungbuk line since the test vehicle was first produced. For the system stabilization, interface verification among the systems including track, structure, catenary and signaling system, not to mention the rolling stock, is very crucial. In the area of wayside structure, the stability of track structure and train run shall be evaluated through the review of impact by increased speed by developed train on track structure. The study thus was intended to evaluate the impact on track while a tilting train is running the curve section, which is vulnerable to accelerated train speed. The analysis of tilting train test running the part of Chungbuk line and Honam line was conducted to identify the impact on existing track performance by tilting train. To identify the movement behavior of each part of track while tilting train, high speed train and traditional train (Mugunghwa and freight train) were running the existing line, wheel load, lateral wheel load, rail bending stress, vertical and lateral displacement of rail and vertical displacement of sleeper were compared and analyzed so as to evaluate the expected impact by tilting train for improving the train speed.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.2
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• pp.125-131
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• 2001

This paper presents a application of vector control strategy to 1.2MVA traction drive for railway vehicle. The vector control required the control of the phase and amplitude of output voltage vector. But in case of traction system for railway vehicle, the one-pulse mode is used at high speed region in order to utilize the link voltage fully. So it is impossible to control the flux and torque axis current instantaneously and independently in the region. So this paper proposes a mixed control algorithm, where the vector control strategy at low speed region and slip-frequency control strategy at high speed region is used. And precise switching technique between the two different control strategy is proposed. The proposed strategy is verified by experimental results with a 1.2MVA traction drive system with four 210kW induction motors.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.64-70
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• 2018

Rollover is a major concern for vehicles with a higher center of gravity and for improving driving performance. This study investigates a tilting system to prevent rollover, which was successfully implemented for high-speed trains. It may be useful to apply the concept of the tilting system to a large truck such as a trailer. Even a small adjustment in the tilting angle can improve the driving stability during a steep turn. The equation of motion was derived from a dynamic model of the trailer with the tilting system. The balance of the centrifugal force and normal force determines the rollover critical speed for a given radius of the turn and load. To obtain a more conservative criterion, the rollover critical state was defined as the instant when any side wheel loses contact with the road. To actuate the tilting system, the optimal tilting angle must be calculated from the steering angle and the vehicle speed. Using a simplified model of a large truck, the effects of the tilting angle and load on the rollover critical speed were investigated.

• Journal of the Korean Society of Safety
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• v.35 no.4
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• pp.9-14
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• 2020

It is necessary to apply a non-contact high-speed scanning system that can measure in real time in order to prevent the dropping and deformation of the main parts of railway vehicles during high-speed running. Recently, research on a scanning system that detects the deformation state of main parts from a video image taken using a high-performance camera has been actively pursued. In this study, we researched an analysis algorithm of a high-speed scanning system that uses a high-performance camera to monitor the deformation and drop-out state of the main components of the running units equipment in real time.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1029-1030
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• 2008

철도에서는 열차가 출발할 때 착력을 향상시키기 위해 레일과 차륜사이에 모래를 살사하게 되는데 이때 ATC(Automatic Train Control : 열차자동제어장치) 신호파형에 영향을 줄 수 있다는 판단에 따라 시험운행하면서 ATC 차상장치인 TVM 430의 CRNB 보드 내에서 살사동작 후 신호파형을 측정하고 분석하였다. 이로 인해 다중화 되어 있는 차상장치 시스템의 동작상태와 살사재료별 ATC 신호파형에 미치는 영향성을 파악할 수 있었으며 향후 살사로 인해 발생되는 문제점 등의 연구에 활용될 수 있을 것으로 판단된다.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.4
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• pp.47-53
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• 2011

The Electric Multiple Unit (EMU) has many types of door system such as sliding door, plug door etc.al. according to customer's requirements. The sliding door is widely used in Korea but has weak point in the noise problem. In the low operation speed, the noise coming from outer side of the EMU is not an important factor. As the speed is higher than before, noise is increased and make a problem. The main cause of noise is the imperfect air tightness in the EMU. The plug door system has advantages for the noise reduction characteristic in the high speed area. We have been developing electric plug-in door. The door is controlled by Door Control Unit(DCU) following the order of Automatic Train Protection (ATP) that is a kind of train signalling system. DCU has to simultaneously open and close the doors and the operation of it is related to the passengers safety. So DCU is a safety device that is important to reliability and safety. DCU is composed of several devices of control, motor driving, Input/Output, communication and power. In this paper, we will describe the functions, characteristic, requirement, subsystem and test results of DCU used for the electric plug-in door.