TY - JOUR

T1 - Wide Area Stabilization of a Magnetic Bearing Using Exact Linearization

AU - Matsumura, Fumio

AU - Namerikawa, Toru

AU - Murata, Noriyuki

PY - 1998

Y1 - 1998

N2 - 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.

AB - 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.

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U2 - 10.1541/ieejias.118.410

DO - 10.1541/ieejias.118.410

M3 - Article

AN - SCOPUS:85024747581

SN - 0913-6339

VL - 118

SP - 410

EP - 416

JO - ieej transactions on industry applications

JF - ieej transactions on industry applications

IS - 3

ER -