• Progress in Superconductivity and Cryogenics
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• v.13 no.1
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• pp.36-40
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• 2011

This paper deals with the design on iron-core shape for superconducting hybrid electromagnet (SH-EM). A proto-type SH-EM was developed by Yonsei University. It is the first step study on the fundamental technology for advanced railroad system development. We proposed the method that reduce the number of cooling systems in order to improve operating efficiency of the SH-EM. The results was obtained by changing of iron-core shape were verified by the FEM analysis. This paper can be expected to suggest useful data for an advanced SH-EM.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.8
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• pp.1572-1576
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• 2011

The electromagnetic levitation(EMS) system is one of the well-known nonlinear system because of its nonlinearity and several control techniques have been proposed. We propose an ${\epsilon}$-scaling partial feedback controller for the ball position control of the EMS system. The key feature of our proposed controller is the use of the scaling factor ${\epsilon}$ which provides a function of controller gain tuning along with robustness. In this paper, we show the stability analysis of our proposed controller and the convergence analysis of the state observer in terms of ${\epsilon}$-scaling factor. In addition, the experimental results show the validity of the proposed controller and improved control performance over the conventional PID controller.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1179_1180
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• 2009

In the maglev system, accurate train position is essential for safe and efficient train operation. Train positioning systems in the maglev systems are different from conventional railway system because railway train has no wheels. And various train positioning principles and systems have been used in maglev systems. In this paper, we study several positioning principles and systems on adapting existing various maglev systems and analyze functional structure of absolute positioning system in ultra high speed maglev system. Then we propose development scheme on absolute positioning system for developing ultra high speed maglev system.

• Journal of the Korean Society for Precision Engineering
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• v.9 no.1
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• pp.53-65
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• 1992

For improving the performance of maglev systems with a combined lift and guidance, it is suggested that the multivariable control systems and a secondary suspension should be added. The former is required to reject both track irregularities in vertical disturbances and wind gusts in lateral disturbances, and the latter to guarantee passengers against an unsatisfied criteria in ride quality. In this paper, bond graph model for the study of nonlinear dynamics of maglev systems with a combined lift and guidance is presented briefly. And, the secondary suspension is analyzed to understand the role of stiffness and damping factors in passive devices. Finally, LQG/LTR mulitivariable control systems are designed for the overall maglev systems with and without secondary suspension, and then the system performances in these two cases are evaluated.

• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.10-13
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• 2007

System requirements (SRs), which describe the technical attributes to be satisfied by a desired system, serve as a fundamental guideline for system development. Standard methods and processes to define SRs are suggested in systems engineering literature. But in practice, we encounter many difficulties in defining and managing SRs since there are few experiences on development of complex systems in accordance with systems engineering processes of development. In this paper, to expanding SRs management experiences in a working-level, we reviewed problems occured in SRs defining process in 'Urban MAGLEV Train Project', and analyzed our activities to adjust and solve the problems.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.6
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• pp.371-379
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• 2000

The 4-pole linear homopolar synchronous motor (LHSM), so called linear inductor motor, is composed of the figure-of-eight shaped 3-phase armature windings, DC field windings, and the segmented secondary with the transverse bar track. To reduce the calculation time, the simplified 3D finite element model with equivalent reluctance and/or permanent magnet is presented. To obtain a clear understanding, propriety and usefulness of the developed model, we compare with the results of simplified 3D FEA, general 3D FEA and test. Consequently, the results of simplified and 3D FEM analysis are nearly identical, but much larger than that of static test at d-axis armature excitation. Therefore the improved FEA model, such as full model with half slot, is needed for the precise analysis.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.2
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• pp.338-341
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• 2015

From the past, maglev technique study(mainly for transportation like maglev) has been done. In the domestic, urban maglev train is practical steps now. High-speed maglev train(550km/h) development comes complete, followed by Japan. This year, system of High-speed maglev train(550km/h) is expected to be verified. This paper simulate FEM model for EMS(Electro-Magnetic Suspension) maglev system and verify tendency of reducing disturbance.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.1133-1136
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• 1999

A magnetic levitation control system is inherently nonlinear and very unstable. Thus there should be a stabilizing compensator network and a negative feedback path using noncontact photoresistor or ultrasonic sensors for the levitation operation. Since the photo sensor plays a key role in the system, the steady-state error and transient performance of the overall system depend on the characteristics of the sensors. But the sensor itself also suffers from nonlinearity, and the magnitude of sensor input heavily depends on environmental conditions. To improve the output performance, we added a linearizing circuit for the sensor characteristics and a disturbance cancelation circuit to avoid sensitive output due to extraneous interfering light.

• Proceedings of the KSR Conference
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• 2006.11a
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• pp.161-169
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• 2006

To develop a Maglev successfully, it is necessary to develop the core technologies such as levitation and propulsion system and construct engineering system which can integrally evaluate performances of Maglev and provide technical reviews parametrically In this paper, we designed the Maglev running performance simulator which can provide decision-making Information for direction of development of Maglev and examination for running performance about the change of various design parameters such as safety and stability, noise, and ride quality. The designed system is an engineering-based system and can be developed using engineering framework by KIMM which can integrate diverse CAE systems in distributed environments and provide systematic information management. And it also provides VR-based visualization and web-based user interface except VR system which requires special hardware system.

• Proceedings of the KSR Conference
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• 2006.11a
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• pp.209-218
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• 2006

This paper presents the comparison and analysis of the power supply system of a Maglev train and conventional electric railway. Even though all Maglev trains have batteries on their vehicles, electric power supply from the ground side is necessary for levitation, propulsion, on-board electrical equipment, battery recharging, and so on. At low speeds up to $100{\sim}150(km/h)$, the Maglev train, generally, uses a mechanical contact, a current collector as same as conventional electric railway. However, at high speeds, the Maglev train can no longer obtain power from the ground side by using a mechanical contact. Therefore, high speed Maglev trains use their own way to deliver the power to the vehicle from the ground. In this paper, the power supply systems of the german, japanese, and korean low- and high-speed Maglev trains have been reviewed.