• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.1
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• pp.18-23
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• 1992

Magnet core and rail of a magnetically levitated vehicle are usually made of highly conductive materials. Accordingly, eddy currents are induced in those members. Eddy currents often lead to a decrement of levitation and guidance force. This paper has calculated the decrement of both forces due to eddy current generated by magnet's vertical and lateral motion. U-shaped electromagnet and rail were chosen as amodel of 2D finite element analysis. Calculated results proved that both forces dropped significantly at high speed. Consequently, effects of eddy current should be considered in designing the magnet and control system.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.136-138
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• 1999

Linear Induction Motors (LIMs) with the long secondary conductor often have joints between the segmented secondary, which are specially used for magnetically levitated high-speed vehicle and elevators. In this paper, the dynamic characteristics of the LIM with joints in the secondary are investigated using the time-stepping finite element analysis. It is supposed that both aluminium conductor and back-iron have joint in the active zone during the analysis. As a result, thrust and normal force ripple which have effects on the motor dynamics and vibration are examined.

• Proceedings of the KIEE Conference
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• summer
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• pp.1343-1345
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• 2004

The inherent pulsating force generation makes the control of switched-reluctance motor quite complicate. So in this paper, an orthogonal scheme that can be applied to the control of LSRM will be presented. By using this scheme, the motor reluctance forces, which are magnetically decoupled and position dependent, can be projected onto sets of stationary axes that are aligned with the motor fixed secondary poles. Hence the electromagnetic forces can be controlled not only for driving the LSRM at its propulsive direction but also for alleviating the load at its normal direction. Simulation results will be provided to show the validity of the proposed scheme.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.718-720
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• 1993

Power conversion system for a magnetically levitated vehicle consists of propulsion inverter to drive linear motor, levitation chopper to drive magnet and power source unit. This paper presents the characteristics of power conversion system in prototype Maglev system. In order to improve performance of electrical equipment IGBT is adopted in a main circuit. Audible noise is reduced to below 60 dB and size is also reduced to 1/3. This system is verified through experiment.

• Journal of the Korean Society for Precision Engineering
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• v.34 no.1
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• pp.41-46
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• 2017

Magnetically levitated (Maglev) vehicles maintain a constant air gap between guideway and car bogie, and thereby achieves non-contact riding. Since the straightness and the flatness of the guideway directly affect the stability of levitation as well as the ride comfort, it is necessary to monitor the status of the guideway and to alert the train operators to any abnormal conditions. In order to develop a signal processing algorithm that extracts guideway irregularities from sensor data, virtual testing using a simulation model would be convenient for analyzing the exact effects of any input as long as the model describes the actual system accurately. Simulation model can also be used as an estimation model. In this paper, we develop a state-space dynamic model of a maglev vehicle system, running on the guideway that contains jumps. This model contains not only the dynamics of the vehicle, but also the descriptions of the power amplifier, the anti-aliasing filter and the sampling delay. A test rig is built for the validation of the model. The test rig consists of a small-scale maglev vehicle, tracks with artificial jumps, and various sensors measuring displacements, accelerations, and coil currents. The experimental data matches well with those from the simulation model, indicating the validity of the model.

• Journal of the Korean Society for Railway
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• v.13 no.1
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• pp.1-8
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• 2010

In domestic developing magnetically levitated (Maglev) vehicle, bogie frames install electromagnets which provide the vehicles to run with levitation and guidance forces; moreover, the linear motors used for traction are integrated into the same mechanical structure. This paper presents the process which predicts the evaluation of life cycle for bogie frame on various running conditions. Durability analysis considering vibration effect is simulated by using random loads resulted from dynamic simulation which takes into account the irregularities of guide rail. And it supports additional weak points which were not examined in static analysis.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.2
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• pp.102-109
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• 2000

The magnetically levitated system technology is highly expected to contribute the new transportation system of the 21st century with its high velocity operation, better riding comforts, friendliness to environment and saving of maintenance labour. Its development has been completed in low speed and in high speed application. In 2005, the Transrapid with 430 km/h speed will go into operation between Berlin and Hamburg[1]. In the year 2000, the realization of JR-Maglev will be basically evaluated for commercial operation[2]. In korea, maglev test vehicle with magnet for levitation and single sided linear induction motor for propulsion is under test at 1 [km] test track in KIMM.[3,4] Here, a transverse flux linear motor in combination with the levitation and the guidance leads to a considerable high power density and high efficiency simultaneously. The designed and measured performance of transverse flux linear motor for maglev system revealed a great potential of system mass reduction.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.6
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• pp.128-135
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• 2004

The author present a modified multi-loop algorithm including feedforward for controlling a 55kW step down chopper in the power supply of Maglev. The control law for the duty cycle consists of three terms. The first is the feedforward term. which compensates for variations in the input voltaga. The second term consists of the difference between the slowly moving inductor current and output current. The third term consists of proportional and integral terms involving the perturbation in the output voltage. This perturvation is derived by subtracting the desired output voltage from the actual output voltage. The proportional and integral action stabilizes the system and minimizes output voltage error. In order to verify the validity of the proposed multi-loop controller, simulation study was tried using Matlab simulink

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.102-105
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• 1991

In recognition of the transportation problems of the present and to prepare for the ever increasing demands of the future, government decided to develop the magnetically levitated train domestically and started R&D program office in Korea Institute of Machinery and Metals(KIMM). This office since has established three step by step goals : first to develop a 40 passenger exhibition vehicle for Daejon EXPO'93, second to develop the low to mid-speed maglev system for urban public transportation by 1997 and finally the high speed inter-city maglev train by year 2001. The first two maglev systems will use attractive levitation-LIM driven technologies and these technologies are the ones currently being developed by this office and others. The maglev train system is a product of wide range of technologies from electro-technologies to civil engineering technologies. Some of the technologies are currently available but more have to be developed in the near future and these technologies are owned by or to be developed by various institutions within the science & technology community. The level of the technologies available at the present time are still very rudimentary and their basis are very narrow. Recently we have made a few successes in terms of levitation and propulsion but they are only with small scale modules and results are very qualitative at best. A great deal of development work has yet to be done to refine the technologies and to gain confidence. Full scale levitation/propulsion modules will be tested on the curved guideway within 6 months by this office and another institution. This paper reviews the current status of the maglev technologies in Korea and discuss the development strategies. The Korean maglev program is very ambitious and the schedule is even more so. A steady financial support and strong system engineering and integration are essential to the success of this program.

• Journal of the Korea Society for Simulation
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• v.20 no.3
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• pp.89-100
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• 2011

The MAGLEV (Magnetically Levitated Vehicle) system, which is under commercialization as a new transportation system in Korea, is operated by means of unmanned automatic control system. Therefore the plan of train operation should be carefully established and validated in advance. In general, when making the train operation plan, the statistically predicted traffic data is used. However, traffic wave can occur when real train service is operated, and the demand-driven simulation technology is required to review train operation plans and service qualities considering traffic wave. This paper presents a method and model to simulate the MAGLEV's operation considering continuous demand changes. For this purpose, we employed the discrete event model which is suitable for modeling the behavior of railway passenger transportation, and modeled the system hierarchically using DEVS (Discrete Event System Specification) formalism. In addition, through the implementation and experiment using DEVSim++ simulation environment, we tested the feasibility of the proposed model and it is also verified that our demand-driven simulation technology could be used for the prior review of the train operation plans and strategies.