Zero-Power Levitation Control Design for a 4-Pole Electromagnet on the Basis of a Transfer Function Approach

Abstract

Electromagnetic levitation (maglev) systems comprised of hybrid electromagnets can suspend a levitating part by use of only the force of permanent magnet(s). However, the system by itself will show instable behavior, to stabilize the system; electric currents are injected to the coils of the electromagnets. The control method in which the currents converge virtually to zero is called as "zero-power control" under steady state regime. The objective of this paper is to present a zero-power controller design scheme by means of a transfer function approach for a voltage excited 4-pole hybrid electromagnet. Furthermore, canonical form of Manabe is integrated into determining process of the gains of the controller polynomials. Consequently, validity of the proposed approach is verified through numerical studies for parameters of an experimental test machine.