Self-sensing magnetic levitation using a LC resonant circuit

A self-sensing magnetic levitation system utilizing a LC resonant circuit is proposed by using the characteristic that the inductance of the magnetic system is varied with respect to the air gap displacement. An external capacitor is added into the electric system to make the levitation system statically stable, which much relieves the control effort required to stabilize the magnetic levitation system of having an intrinsic unstable nature. For the realization of the self-sensing magnetically levitated system, an amplitude modulation/demodulation method is used with a positive position feedback controller. Experimental results are presented to validate the proposed method. (C) 1999 Elsevier Science S.A. All rights reserved.