• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.117-125
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• 2017

Research on Maglev (Magnetic Levitation) train is currently being conducted in Korea, concerning Urban Transit (110 km/h of maximum speed), semi-high-speed (200 km/h of maximum speed), and high-speed (550 km/h of maximum speed) trains. This paper presents a research study on the levitation and guidance systems for the Korean semi-high-speed maglev train. A levitation electromagnet was designed, and the need for a separate guidance system was analyzed. A guidance electromagnet to control the lateral displacement of the train and ensure its stable operation was then also designed, and its characteristics were analyzed. The dynamic performance of the designed levitation and guidance electromagnets was modeled and analyzed, using a linearized modeling of the system equations of motion. Lastly, a test setup was prepared, including manufactured prototypes of the designed system, and the validity of the design was verified and examined with performance evaluation tests.

• Journal of KSNVE
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• v.6 no.3
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• pp.357-362
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• 1996

The magnetic levitation system has great advantages, such as little friction, no lubrication, no noise and so on. But the magnetic levitation system need a stabilizing controller because it is a unstable, system in natural and it need a sensor for displacement measurement to control the system. In this paper, we proposed a sensorless method to measure the gap between the magnetic pole and the levitated object with application the inductance characteristic which vary according to gap. We made a driving circuit which supply simultaneously the control input PWM(Pulse Width Modulation) signal and the carrier PWM signal to estimate the gap. Because the inductance is a function of gap, and the current of the carrier signal is a function of the inductance, we could estimate the gap from the measurement of the current of the carrier signal. Finally, we investigated the validity of the proposed method through the experimental results.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.7
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• pp.875-880
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• 2016

A new hybrid permanent magnet biased magnetic levitation actuator (maglev) is developed. This new maglev actuator is composed of two C-core electromagnetic cores separated with two permanent magnets. Compared to the conventional hybrid maglev actuators, the new actuator has unique flux paths such that bias flux paths are separated with control flux paths. The control flux paths have minimum reluctances only developed by air gaps, so the currents to produce control fluxes can be minimized. The gravity load can be compensated with the permanent magnet bias fluxes developed at off-centered air gap positions while external disturbances are controlled with control fluxes by currents. The consumed power to operate this levitation system can be minimized. 1-D magnetic circuit model is developed for this model such that the flux densities and magnetic forces are extensively analyzed. 3-D finite element model is also developed to analyze the performances of the maglev actuator.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.11
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• pp.75-80
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• 2000

Recently, there are a great many research for magnetic levitation system. In case electromagnet is operated as the actuator of control system, first of all, we must analysis about an electromagnet. Important parameters of this system are inductance(L) and resistance(R) which are induced from the coil of electromagnet. And attractive force equation is also important. If the load of this system is large, phase delay is caused by self-inductance effect. Because this delay effect cause stability of whole magnetic evitation system to grow worse, a measures to diminish time constant must have been taken. And the linearized attractive force equation which is used at small range of the operating point is compensated to use at larger range, thus the experiment of magnetic levitation system will get a better result.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.303-304
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• 2009

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1024-1031
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• 2008

The performance of magnetic levitation controller is affected from not only levitation control algorithm but also the interaction between compositing system, so it is important to design maglev system considering the character of magnetic levitation controller in order to get the required performance of Maglev. The factors affecting the levitation controller of maglev are the dynamics of levitation magnet, the carrying weight of the overall system, the normal force and lateral force of traction motor and rail condition. In this paper the interaction between magnet and vehicle weight is analysed on side of stability of levitation controller in order to get the required performance of levitation controller.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.2
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• pp.129-135
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• 2014

In the paper, we propose a design method for the logistics transportation system using magnetic levitation that has a good characteristics without mechanical friction, noise and dust. The proposed transportation system consists of a levitation control system and a propulsion control system. Magnetic levitation system is an electromagnetic suspension system in which electromagnet generates magnetic attractive force and the attractive force pulls the rail. We design a PID controller for the current control of electromagnets. We use linear induction motors for propulsion of the proposed logistics transportation system and adapt the space vector PWM method for the propulsion control system. The proposed transportation system using magnetic levitation is verified performances through levitation and propulsion experiments.

• Journal of the Korean Institute of Intelligent Systems
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• v.27 no.2
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• pp.106-112
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• 2017

In the paper, we propose a levitation and a propulsion controller for the magnetic levitation logistic transportation system. The levitation controller is designed considering the mutual influence of the electromagnets to minimize roll and pitch movements. In order to solve the structural disadvantages of the magnetic levitation transportation system, we improve the problem of the existing controller by applying the exponential filter to the reference input. DSP-based control hardware is developed and the levitation control method is verified by levitation experiments to the air gap goal. The propulsion controller uses the space vector voltage modulation method. The propulsion controller is designed to follow the position and velocity profile by detecting the absolute position from the bar code information attached to the rail. The position control result shows satisfactory performance through the propulsion control reciprocating motion experiment.

• Tribology and Lubricants
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• v.14 no.4
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• pp.44-50
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• 1998

This paper describes the simulation of the levitation force between permanent magnet and high Tc(critical temperature) superconductor(HTSC). Levitation force is evaluated numerically on the basis of the magnetic vector potential method and the critical state model. The superconductor is approximated to 2-D slab model. By performing computations, the following characteristics have been investigated: the process of the generation of hysteresis, the various hysteretic behaviors. The characteristics of hysteresis are important for the application to magnetic bearing, for the damping and the nonlinear stiffness is related to hysteresis.

• Journal of Power System Engineering
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• v.14 no.1
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• pp.65-70
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• 2010

Magnetic levitation system is nonlinear and inherently unstable, so it is difficult to control. Analog control circuit was widly used as the controller of magnetic levitation system, but digital controller is now substituted for analog controller according to development of digital electronics. In this study, Atmel AVR series, ATmega 128 which is a kind of $\mu$-processor for digital controller is used because the chip is cheap and popular. We designed and made ATmega 128 one-board controller and aimed to verify validity through the experiance of levitation response.