• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.185-187
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• 2008

This paper proposed design and development of a photo voltaic (PV) array fed induction motor drive. A drive system using a chopper circuit to track maximum power from the PV for different solar insolation and a current controlled voltage source inverter (CC-VSI) to optimally match the motor to PV characteristics is presented. The model equations governing interaction of torque and flux producing components of motor current with available solar power is developed for the operation of the system at optimum efficiency. Performance of the system is presented for different realistic operating conditions, which demonstrates its special features for applications such as solar water pumping system, solar vehicles and floor mills located in hilly and isolated areas.

• Journal of Power Electronics
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• v.2 no.3
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• pp.155-161
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• 2002

This paper presents a maximum power point tracking algorithm for Photovoltaic array using only instantaneous output current information. The conventional Hill climbing method of peak power tracking has a disadvantage of oscillations about the maximum power point. To overcome this problem, we have developed an algorithm that will estimate the duty ratio corresponding to maximum power operation of solar cell. The estimation of the optimal duty ratio involves, finding the duty ratio at which integral value of output current is maximum. For the estimation, we have used the well know Lagrange's interpolation method. This method can track maximum power point quickly even for changing solar isolation and avoids oscillations after reaching the maximum power point.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.366-368
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• 2002

Communication based train control system is applied regularly worldwide. And this system may be used in domestic soon. Communication based train control system does not depend on conventional track circuit. Therefore, position and distance control of train to prevent collision with leading train may become important safety factor. This paper developed collision avoidance algorithm to control trains of several units efficiently for this. In developing a collision avoidance algorithm, it is desirable to avoid the need for additional system. Additional system restricts the development of the algorithm by limiting the effectiveness of the algorithm to only those areas where the additional system can be afforded and has been installed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.208-213
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• 2003

A note-book PC has become thinner in recent years. And optical disc drives are required to have high memory capacity. Therefore, the actuator of optical disc drives must be thinner and have disc tilt compensation function for high density memory. In this paper, the hybrid type actuator is investigated for 3-axis ultra-slim actuator. A 3-axis ultra-slim actuator is designed by using the modal analysis of the actuator and the electromagnetic analysis of magnetic circuit to achieve dynamic characteristics and magnetic flux density for high sensitivity, respectively. Also, magnetic force between tilt magnet and tilt yoke is investigated to find the influence on the DC sensitivity in the focus and track directions.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.449-451
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• 2001

This study presents a study on modified algorithm to operating train simulation of AT feeding systems. In this study equivalent impedance is constructed by $Z_c,\;Z_r,\;Z_f,\;Z_{cr},\;Z_{rf},\;Z_{fc}$. The train current flows through the all auto-transformer corresponding to track impedance. To calculate train voltage from analyzing the railway systems, the algorithm is based on the K. C. L, K. V. L, superposition and circuit separation method. Multi-train's voltages are determined by calculating the catenary voltage at each train's position and adding up these train's voltage drop. Case studies use a field operational data, show that the proposed method is easily applied.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1130-1131
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• 2006

본 논문은 고속선에 사용 중인 UM71-C 궤도회로에 대한 전기적인 특성에 관한 시뮬레이션 실행결과를 나타낸다. 고속선 운행선상의 샘플개소를 선정하여 환경에 따른 선로정수를 구하고 전송라인의 특성임피던스와 전파정수를 반영시켜 레일전압과 전류에 대한 시뮬레이션을 수행하였으며, 차상검측시스템에서 측정되어진 검측데이터 파형과 비교하였다. 이러한 모델링 작업은 궤도회로 구성요소의 기능저하를 사전 예측하여 열차의 안전운행을 확보하기 위한 기초자료로 사용되어 질 수 있으며, 또한 차상검측시스템에서 얻어진 검측데이터와의 비교를 통해 유지보수에 활용 가능한 활용지침 및 분석기준을 작성하기 위해 필요하다.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1112-1114
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• 2006

Tilting train has been developed to increase the operational speed of the trains on conventional lines which have many curves. This train are tilted at curves to compensate for unbalanced carbody centrifugal acceleration to a greater extent than compensation produced by the track cant, so that passengers do not feel centrifugal acceleration and thus trains can run at higher speed at curves. This paper show that results of normal capacity calculations of the electrical equipments such as Main transformer, PWM converter, VVVF inverter, traction motor in TTX(tilting train express) with maximum operation speed 180km/h

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1229-1234
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• 2004

Accurate and reliable tracking system is essential for the central train control system. There are two systems widely being used. one is the fixed block system which utilizes the track circuit for the detection of train position. the other is the moving block system which has the advantage over the former since it enables shorter radio signal for the train position detection. In this paper a new algorithm is proposed which uses signal's phase difference of arrival to detect the train position. Experimental verification of the algorithm is presented in the paper.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.4
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• pp.226-235
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• 2014

Nowadays, railroads are considered the most efficient form of mass transportation. Furthermore, it is necessary that railroads be paired with state-of-the-art safety equipment. Unfortunately, it is impossible to prevent 100% of accidents that may be caused by system or human errors. In order to prevent future accidents, RAMS activity and Functional Safety Certification are required for new systems that are under development. In this paper we evaluate the necessity of the application of RAMS and the performance of RAMS in the system development process. We also explore the Safety Evaluation Procedure required for RAMS certification.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.281-283
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• 1998

The 4-poles LHSM with transverse bar track was designed on the base of the performance equations and the equivalent circuit model. However, the magnetic shape factors, such as Carter's and Green's coefficients, $B_{min}/B_{max}$ and leakage factors, were important in the design and analysis of LHSM. Consequently, these coefficients were computed from the analytical expressions and examined from FEM analysis in detail.