An Efficient Method for Stability Analysis for Active Magnetic Bearing System

The dynamic properties of active magnetic bearings are functions of rotor excitation frequencies, not rotor speed. Existing rotordynamic analysis requires trial-and-error iterations to find rotor-bearing system damped natural frequencies. A two-level, finite-elementbased rotordynamic computer program with an efficient root-searching algorithm for stability analysis has been developed. Given an initial estimate of the first natural frequency, the program is able to automatically search for all the natural frequencies. A numerical example, which has several very close natural frequencies, is presented to demonstrate the program's capability.