Low-bias control of AMB subject to voltage saturation: state-feedback and observer designs

• Published in: IEEE transactions on control systems technology Vol. 13; no. 2; pp. 262 - 273
• Main Authors: Tsiotras, P., Arcak, M.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.03.2005; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Asymptotic properties; Batteries; Bearings, bushings, rolling bearings; Chemicals; Computer science; control theory; systems; Control system synthesis; Control theory. Systems; Design engineering; Drives; Electric potential; Exact sciences and technology; Extraterrestrial measurements; Flux; Flywheels; Magnetic field measurement; Magnetic levitation; Mathematical models; Mechanical engineering. Machine design; Modelling and identification; nonlinear systems; Nonlinearity; Observers; passivation; Power generation; Saturation; Space vehicles; Voltage control; Wheels; State feedback; Saturation state; Bias; Non linear control; Control synthesis; Modeling; Passivity; Asymptotic stability; Active system; Magnetic control; Reduced order systems; System identification; State estimation; Saturation; passivation; magnetic levitation; nonlinear systems; Magnetic field measurement; Magnetic bearing; Global stabilization; Small gain theorem; Asymptotic approximation; Non linear observer; observers; Magnetic suspension
• ISSN: 1063-6536; 1558-0865
• DOI: 10.1109/TCST.2004.839562

This paper addresses the problem of low-bias control for an active magnetic bearing (AMB) subject to voltage saturation. Using a generalized complementarity flux condition, a simple, three-dimensional (3-D) flux-based model is used to describe the dynamics of the low-bias mode of operation. Several stabilizing controllers are derived by applying recent results from nonlinear control theory. Specifically, the asymptotic small-gain theorem of Teel and passivity-based ideas are instrumental in our designs. Both soft and hard saturation constraints are accommodated. When flux measurements are not available, a nonlinear reduced order observer is proposed to estimate the flux. We show global asymptotic stability for all controller-observer interconnections. Numerical simulations against a high-fidelity AMB model show the effectiveness of the proposed control designs.