Honor Paper: A Nonlinear Simulation Model for Active-Magnetic Bearing Actuators

A magnetic network theory is presented to model the stator, rotor and airgap flux paths of active magnetic bearing actuators. Nonlinear empirical magnetization laws including hysteresis and saturation of the ferromagnetic core materials are employed. Open loop multidimensional state space equations for magnetic bearing actuators are carried out to determine the magnetic flux density to field strength trajectories within any path of the bearing network model. Nonlinear actuator airgap forces are calculated, and the governing dynamic equations of an active magnetic bearing are presented in a compact matrix form. A numerical example is employed for a closed loop voltage controlled system of a radial 8-pole bearing.