• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.1
• /
• pp.71-78
• /
• 2002

This paper is concerned with the design and implementation of magnetic damper system to reduce the vibration of suspension system actively. Cylindrical type electro-magnetic actuator with permanent magnet is analyzed and effective controller design is made. Magnetic force analyzed and transfer function for the total system is determined by experimental data using error minimization method. For experiments, simple suspension structure system is utilized, in which a magnetic damper composed of permanent magnet and digital controller is attached. In order to drive the system, bipolar power amplifier of voltage control type is utilized. Stable and high speed control board is used to perform digital control logic for the given system. This paper shows that the magnetic damper system using phase-lead controller excellently reduces vibration of 1-D.O.F (degree of freedom) suspension system.

• Journal of Magnetics
• /
• v.18 no.3
• /
• pp.370-374
• /
• 2013

This paper introduces an innovative hybrid array consisting of both permanent and electro magnets. It will enable us to develop an active control mechanism for underdamped electro-dynamic suspension (EDS) Maglev systems. The proposed scheme is based on the Halbach array configuration which takes the major technical advantage from the original Halbach characteristics: a strongly concentrated magnetic field on one side of the array and a cancelled field on the opposite side. In addition, the unique feature of the proposed concept only differs from the Halbach array with permanent magnets. The total magnetic field of the array can be actively controlled through the current of the electro-magnet's coils. As a result, the magnetic force produced by the proposed hybrid array can also be controlled actively. This study focuses on the magnetic characteristics and capability of the proposed array as compared to the basic Halbach concept. The results show that the proposed array is capable of producing not only an equivalent suspension force of the basic Halbach permanent magnet array but also a controlled mode. Consequently, the effectiveness of the proposed array confirms that this study can be used as a technical framework to develop an active control mechanism for an EDS Maglev system.

• Proceedings of the Korean Magnestics Society Conference
• /
• 1995.05a
• /
• pp.28-29
• /
• 1995

• Proceedings of the KSR Conference
• /
• 2004.06a
• /
• pp.1303-1307
• /
• 2004

MAGLEV is the vehicle which can run in levitated condition by the electro-magnets, and the vehicle can run without any contact condition. In MAGLEV system achieving a high magnetic field for minimum weight is a noteworthy goal. Unfortunately the two aspects of this goal high field and low weight are contradictory. Suitable designs must be sought using optimization techniques. In this paper, magnet attraction force is calculated and conformed by experimental data for designing a electro-magnet.

• Proceedings of the KIEE Conference
• /
• 2000.07e
• /
• pp.13-16
• /
• 2000

This paper developed a manufacturing method for resin magnet contained rare earth element and synthetic resin. Use this manufacturing method, developed a electro wave absorbent material and plant growth promote machine. Result of experiments shown to have excellent on bean sprouts cultivate, computer monitor, television monitor and cellular phone etc.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2015.08a
• /
• pp.135-135
• /
• 2015

Tubes are of extreme importance in industries as for fluid channels or wave guides. Furthermore, some weapon systems such as cannons use the tubes as gun barrels. To increase the service life of such tubes, a protective coating must be applied to the tubes' inner surface. However, the coating methods applicable to the inner surface of the tubes are very limited due to the geometrical restriction. A small-diameter cylindrical magnetron sputtering gun can be used to deposit coating layers on the inner surface of the large-bore tubes. However, for small-bore tubes with the inner diameter of one inch (~25 mm), the magnetron sputtering method can hardly be accommodated due to the space limitation for permanent magnet assembly. In this study, a new approach to coat the inner surface of small-bore tubes with the inside diameter of one inch was developed. Instead of using permanent magnets for magnetron operation, an external electro-magnet assembly was adopted around the tube to confine the plasma and to sustain the discharge. The electro-magnet was operated in pulse mode to provide the strong axial magnetic field for the magnetron operation, which was synchronized with the negative high-voltage pulse applied to the water-cooled coaxial sputtering target installed inside the tube. By moving the electro-magnet assembly along the tube's axial direction, the inner surface of the tube could be uniformly coated. The inner-surface coating system in this study used the tube itself as the vacuum chamber. The SS-304 tube's inner diameter was 22 mm and the length was ~1 m. A water-cooled Cu tube (sputtering target) of the outer diameter of 12 mm was installed inside of the SS tube (substrate) at the axial position. The 50 mm-long electro-magnet assembly was fed by a current pulse of 250 A at the frequency and pulse width of 100 Hz and 100 usec, respectively. The calculated axial magnetic field strength at the center was ~0.6 Tesla. The central Cu tube was synchronously driven by a HiPIMS power supply at the same frequency of 100 Hz as the electro-magnet and the applied pulse voltage was -1200 V with a pulse width of 500 usec. At 150 mTorr of Ar pressure, the Cu deposition rate of ~10 nm/min could be obtained. In this talk, a new method to sputter coat the inner surface of small-bore tubes would be presented and discussed, which might have broad industrial and military application areas.

• Proceedings of the KIEE Conference
• /
• 1995.07a
• /
• pp.46-49
• /
• 1995

This paper deals with characteristics of magnet that the levitation and guidance forces at static state and we tested and evaluated its. Also we compared to effect of levitation force with material and shape of guide way, focus on evaluation and method of test for the magnet of Urban Transit Maglev vehicle.

• Proceedings of the KSR Conference
• /
• 2010.06a
• /
• pp.830-837
• /
• 2010

Since it started the researches on a maglev train on 1960, Germany and Japan arrived to putting to practical use level and accomplished most tests from their test-line. Korea is in progress the preparation for a practical use of low-speed maglev train in 110 [km/h] class and Korea Railroad Research Institute(KRRI) is in progress of a research about core technology of maglev system for high-speed tube train of 700 [km/h] class. In this paper, authors suggest an effective design method of Linear Synchronous Motor(LSM) for high-speed tube train of 700 [km/h] class which has a wound type electro-magnet. Then, authors calculate a variety of properties by changing speed of the LSM model which is designed by a method based on some theoretical equations. Then, authors verify the validity of the method based on some theoretical equations through a verification of property values by Finite Element Method(FEM) analysis method. Finally, in order to design a shape of pole-shoe part of LSM electro-magnet which is hard to design with a basic design method, authors analyze a transition of property values by changing a pole-shoe width and current of the electro-magnet through an analytical method by FEM.

• Proceedings of the KIEE Conference
• /
• 2003.04a
• /
• pp.97-100
• /
• 2003

Recently, the generators for wind turbine have been manufactured with high output power such like MW class machine in order to reduce the generation cost and to increase the energy efficiency. At the same time, direct-driven generators for wind turbine have been developed and researched, which have easy maintenance and high efficiency by simplification the system through the removal of the gear box. In this paper, at first, the advantage and disadvantage between the direct-driven generator system and conventional indirect-driven system are compared. And secondly, the permanent magnet generator (PMG) for wind turbine has been rapidly improved to cope with the recent trend which requires the high power output Per one machine and the convenience for maintenance, and the PMG is adequate for direct driven system and suitable for high-efficiency and light weight. So, the characteristics and technical trend of the PMG for wind turbine is examined. At last, a suitable technical trend for development of the permanent magnet generator for wind turbine is proposed.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.15 no.2 s.95
• /
• pp.156-160
• /
• 2005

We design a new actuator of 3-axis motion for high performance optical devices. The actuator makes it possible to control the tilting motion by using moving magnet and PCB-coil, which have benefits in price and manufacturing. To predict the characteristics of the actuator, especially the effect of moving magnet, finite element method and electro-magnetic analysis were used. By comparing simulation data with experimental results, we verified the accuracy of the simulation and the superiority of the present.