Wide Area Stabilization of a Magnetic Bearing Using Exact Linearization

Fumio Matsumura, Toru Namerikawa, Noriyuki Murata

Research output: Contribution to journalArticle

Abstract

An active magnetic bearing (AMB) is a bearing to suspend a rotor by magnetic forces without any contact. Feedback control is indispensable for a magnetic bearing, because it is essentially an unstable system. To design a feedback control system, a linear mathematical model of the plant is convenient, however the force of electromagnet is highly nonlinear. Then usually a linear approximation around the operating point is employed, but the obtained linearized model can not express the exact behavior of the system at any other operating points. In this paper, we discuss the wide area stabilization of magnetic bearing using exact linearization approach. At first, we derive a nonlinear mathematical model for a magnetic bearing, then we show this nonlinear system is belong to a class of exactly linearizable nonlinear systems. Next, by using exact linearization method, we transfer the nonlinear model of a magnetic bearing to a linear time invariant state model in spite of change of the operating point and the rotational speed of the rotor. Then we construct the state feedback control system by conventional LQ method. Finally, we evaluate the validity of our proposed method by experiment.

Original languageEnglish
Pages (from-to)410-416
Number of pages7
JournalIEEJ Transactions on Industry Applications
Volume118
Issue number3
DOIs
Publication statusPublished - 1998
Externally publishedYes

ASJC Scopus subject areas

  • Industrial and Manufacturing Engineering
  • Electrical and Electronic Engineering

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