The development and application of permanent-magnet EDS based on Halbach structure
With the permanent-magnet EDS (Electro-dynamic Suspension) system as the background, rectilineal PM Halbach structure is introduced. The theory and stability of permanent-magnet EDS system are analyzed which concludes that permanent-magnet EDS system is of greater advantage under high speed condition. Then two present projects based on the the permanent-magnet EDS which aim at actual application, the GA urban maglev train and the Inductrack rocket launch assist system in US, are introduced in details. Adopting double layers PM halbach structure#GA urban maglev train solves the shortage that the levitation-drag ratio is smaller in low speed condition. The Inductrack rocket launch assist system can save fuel and send more payloads. Finally, Permanent EDS research development status home is generalized.
Passive damping in EDS maglev systems.
There continues to be strong interest in the subjects of damping and drag forces associated with electrodynamic suspension (EDS) systems. While electromagnetic drag forces resist the forward motion of a vehicle and therefore consume energy, damping forces control, at least in part, the response of the vehicle to disturbances. Ideally, one would like to reduce the drag forces as much as possible while retaining adequate damping forces to insure dynamic stability and satisfactory ride quality. These two goals turn out to be difficult to achieve in practice. It is well known that maglev systems tend to be intrinsically under damped. Consequently it is often necessary in a practical system design to enhance the damping passively or actively. For reasons of cost and simplicity, it is desirable to rely as much as possible on passive damping mechanisms. In this paper, rough estimates are made of the passive damping and drag forces caused by various mechanisms in EDS systems. No attention will be given to active control systems or secondary suspension systems which are obvious ways to augment passive damping mechanisms if the latter prove to be inadequate.
Eddy Currents in Finite Conducting Sheets
This paper deals with eddy currents in bounded plane conductors. Specifically, we are concerned with the semi‐infinite plane sheet and a conducting disk. The eddy‐current distribution in a perfectly conducting sheet or disk due to a magnetic monopole source is obtained by a technique due to Sommerfeld. Sommerfeld's analysis for the disk is incomplete, but we have completed the derivation for this geometry. The eddy‐current decay in a semi‐infinite sheet of finite conductivity is solved by an approximate technique. The results are used to calculate lift, drag, and transverse forces on a magnetic monopole moving parallel to the edge of a semi‐infinite sheet of finite conductivity.