Behavior of an eddy current magnetic bearing.

摘要

The perturbation method (PM) in conjunction with the symbolic computing software "MATHEMATICA" is employed to solve Maxwell's equations to obtain the theoretical results of forces, stiffness and damping coefficients for a simplified eddy current magnetic bearing (ECMB). In addition, a finite element method software "FLUX2D" and some deliberately designed experiments are employed to check some of the results obtained by the perturbation method. Finally, the results are used to evaluate the dynamic behavior of the eddy current magnetic bearing, and are extended to conjecture concerning the prospect of a similar application, Maglev (Magnetically Levitated High Speed Trains).; The theoretical results of forces, stiffness and damping coefficients obtained by the perturbation method show that such kind of bearing has extremely low damping, probably negative, and moderately low stiffness and forces, compared to ordinary bearings. The dynamic aspect of the bearing shows possible vibration sources due to the high cross-coupled stiffness (K{dollar}sb{lcub}rm xy{rcub}{dollar}). Unless advanced high temperature superconducting materials become practical, eddy current magnetic bearings will not provide a reasonable application.; Data are also obtained by inputting the presumed Maglev features to the perturbation method solutions. It is found that the eddy current type magnetic suspension is more practical in the large scale application (Maglev) than in small scale application (ECMB); one reason is the poor dynamic performance for the ECMB, such as low forces, stiffness and negative damping, and the other reason is that the enormous heat generation during the process imposes a technical problem for the ECMB, but not for the Maglev application.