Chang-Wan Ha

Analysis and Control of the Electromagnetic Coupling Effect of the Levitation and Guidance Systems for a Semi-High-Speed MAGLEV Using a Magnetic Equivalent Circuit

This paper describes the levitation and guidance characteristics of a semi-high-speed magnetic levitation (MAGLEV) vehicle. For a MAGLEV, which operates at 200 km/h, the guidance magnet is essential for high-speed operation at curves and against a side wind. The levitation and guidance magnets are electromagnetically and dynamically coupled, because both are used in a single rail. Because of the interactions between the levitation and guidance systems, clear establishment of their correlation is required for robust and stable control. We identify the electromagnetic/dynamic correlation of the levitation and guidance systems of the MAGLEV using a magnetic equivalent circuit and motion equations. A controller is developed to realize stable control by considering the system correlation. The control properties are obtained through simulation to achieve stable levitation and guidance.

Analysis and Experimental Evaluation of Normal Force of Linear Induction Motor for Maglev Vehicle

This paper presents the analysis and experimental of the effective normal force and power consumption in a maglev vehicle. A maglev vehicle employs the electromagnets as suspension and linear motors for propulsion. These components give the higher ride comfort but suffered from energy efficiency. Therefore, a vector control-based algorithm and various air gaps are employed to increase the propulsion efficiency and lower the system energy consumption. The effective levitation load according to the levitation gap and normal force of a linear induction motor is calculated by power consumption in a levitation system and compared with finite-element analysis results. The experiment is carried out with the full-scaled train in test line and the efficiency of a propulsion system is also presented.

Analysis and Control of Electromagnetic Coupling Effect of Levitation and Guidance Systems for Semi-High-Speed Maglev Train Considering Current Direction

A semi-high-speed magnetic levitation (maglev) train with a maximum speed of 200 km/h is being developed in Korea. It utilizes linear induction motors for propulsion and adopts electromagnetic suspension for levitation. For high-speed operation, guidance systems should be adopted to stabilize the train especially on curved tracks. For compatibility of the rail with previously developed urban maglev trains, the installation of the guidance electromagnet has to be restricted to be placed near the levitation electromagnet. Owing to the spatial closeness, mutual magnetic flux by the levitation and guidance electromagnets is produced at an overlapping portion of the rail. For stable control of the two systems, the coupling effects must be analyzed, because the levitation and guidance electromagnets are not operated independently. This paper aims to analyze the coupling effects by considering the magnetic field and a magnetic equivalent circuit. This paper suggests levitation and guidance systems for the semi-high-speed maglev train by considering each electromagnetic characteristic depending on the current direction.

Passive Maglev Carrier Control with Consideration of Pitch Motion

This research aims to develop core technologies for passive carrier (no power in carrier itself) transfer system. The technologies are passive levitation, propulsion, and guidance, which can be great benefits for semiconductor and display manufacturing industries. Passive maglev carrier is necessary to precise position control for quiet and stable transfer operation. However, the structural characteristics of carrier and the installation errors of gap sensors cause the pitch motion. Hence, the controller design in consideration of pitch motion is required. This study deals with the reduction control of carrier pitch motion. PDA controller and PDA controller with pitch control are proposed to compare the pitch angle analysis. The pitch angle and the levitation precision are measured by experiment. Finally, the optimized design of pitch controller is presented and the effects are discussed. † Corresponding Author, einses@kimm.re.kr C 2016 The Korean Society of Mechanical Engineers 이영학 · 김창현 · 하창완 · 박도영 · 양석조 · 임재원 214

Thrust and efficiency analysis of linear induction motors for semi-high-speed Maglev trains using 2D finite element models

The semi-high-speed magnetic levitation (Maglev) train currently being developed in Korea uses linear induction motors (LI Ms) for thrust. LI Ms have very high operation reliability and relatively low production costs. However, when applied to Maglev trains, their operation efficiency is lowered because of the large air gaps. Therefore, this paper analyzes in detail the driving force, normal force, and efficiency of LIMs applied to Maglev trains, using finite element models. The entire operating area of LIMs is divided into a rated driving force region and a rated output power region; the driving force, normal force, and efficiency are interpreted and analyzed.

Magnetic Levitation Control through the Introduction of Bogie Pitch Motion into a Control Law

The uneven reaction surface profile facing the lift magnets in attractive Maglev vehicles naturally brings about pitch motion of the bogie. In particular, in the placement configuration of the long stator of the linear synchronous motor (LSM) on the track for high-speed propulsion, surface irregularities and the offsets between the stator packs create measurable airgaps, i.e., the clearance between the magnet and the stator, with discontinuously extreme values, resulting in bogie pitch motion. This occurs because the airgap velocities and accelerations derived by the differentiations of the measured air-gaps are used to determine the voltages applied to the magnets. This paper incorporates bogie pitch motion into a control law for each magnet controller to reduce the variations in both the airgap and the pitch angle. The effectiveness of the proposed method is analyzed using a full-scale Maglev vehicle running over a test track.

Control characteristics of passive maglev transport system

Recent OLED display manufacturing process requires non-contact conveyor systems which do not generate particles for increased productivity. To avoid supplying power and heating in vacuum, a passive magnetic levitation (maglev) transport system can be a promising solution because it has neither sensor nor actuator in moving carriers and all active components are installed on the ground. In this paper, we deal with the design and control characteristics of the passive maglev transport system. The levitation and guidance system has redundancy and needs to be properly switched. The proposed guidance system can generate bi-directional motion using one electromagnet and the guidance system is designed and analyzed in details using FEM tools. The control characteristics were analyzed through impact tests using the manufactured passive maglev transport system.

Development of high accuracy of magnetic levitation transport system for OLED evaporation process

Recently, in the manufacturing process of flat panel displays, mass production method of the in-line system has been emerged. In particular, the next generation OLED display manufacturing process, horizontal in-line evaporation process has been tried. It is important for the success of OLED inline evaporation process to develop a magnetic levitation transport system capable of transferring a carrier equipped with a mother glass with high accuracy without any physical contact along the rail under vacuum condition. In the case of existing wheel-based transfer system, it is not suitable for OLED evaporation process requiring high cleanliness. On the other hand, the magnetic levitation transport system has an advantage that it does not generate any dust and it is possible to achieve high-precision control because there are not non-linear factors such as friction force. In this paper, we introduce the high accuracy magnetic levitation transport system for OLED evaporation process currently under development and design of levitation controller using cascade control consisting of current control (PI) and airgap control (PID).

Experimental verification and electromagnetic analysis for force performance of levitation and guidance electromagnet in semi-high-speed Maglev train

This paper investigates the electromagnetic coupling effect between the levitation and guidance systems of a semi-high-speed Maglev train. Semi-high-speed Maglev trains are equipped with active lateral guidance systems to deal with crosswinds and high-speed operation in curves. Guidance magnets are located near the levitation system and share the same core, thus causing electromagnetic coupling. Both finite element analysis and a magnetic equivalent circuit were used to test and analyze the magnetic coupling effect. Using this magnetic equivalent circuit, a linear control model for the electromagnets was also obtained. And the validity of the obtained experimental results was verified using a custom-made full-sized model, and the system applicability was analyzed.

Design and control characteristics of guidance system for passive maglev transport system

Recent OLED display manufacturing process requires non-contact conveyor systems not generating particles to increase productivity. To avoid supplying power and heating in vacuum, a passive maglev transport system can be a promising solution because it has no actuators in moving carriers and all actuating electromagnets are installed on the ground. In this paper, we deal with the design and control characteristics of the guidance system for the passive maglev transport system. The proposed guidance system can generate bi-directional motion using one electromagnet and the guidance system is designed and analyzed in details using FEM tools. The guidance control characteristics were analyzed through impact tests using the manufactured passive maglev transport system.