Coupled Electro-Thermal Modeling of Magnetic Bearing Systems

This paper presents coupled electromagnetic and thermal modelling of active magnetic bearing systems. In magnetic bearing systems, the electric, magnetic, eddy current and thermal processes are intrinsically coupled. There are two major sources of heat generated in magnetic bearing: the heat generated by the DC current in the excitation coils and the heat generated by the eddy current in the high speed rotating parts. The eddy current is not uniformly distributed in the rotor and thrust bearing. In this paper, the magnetic filed is first modelled using 2D/3D finite element analysis (FEA). The eddy current information obtained in FEA is then transferred to thermal FEA model to perform thermal analysis. Hot spots can be identified in this procedure. By using Ansoft’s Electromagnetic package, the 2D/3D FEA is coupled with thermal FEA through e-Physics. Data can be automatically linked and exchanged between the magnetic and thermal models. The experiment data on a test platform validated the proposed model.