Thermal Simulation of Rotating Machine Equipped with Active Magnetic Bearings

Lately higher speed and higher power drive technology is more demanding in many industrial application such as several kinds of turbo machinery ex. compressor, expander and generator relating to various kind of gas processing. Active magnetic bearing should be a one of potential device to support such high power density rotor. On the other hands, high power densitywill induce several technical problems. One of these technical problems is thermal problem. Hence the rotor supported by active magnetic bearing can only dissipate generated heat by means of convection and radiation (no conduction), elongation of the rotor may cause serious change in mechanical air gap, especially axial air gap between rotor and touch down bearings shall be carefully considered. For handling this problem, thermal analysis of entire machine is needed.[1] The mathematical model of entire machine shall be consisting of rotor and all of non-rotating components such as activemagnetic bearing’s actuator,motor stator, housing and cooling jacket. Further more it is better to simulate transient thermal behavior of each machine components, author has developedMatlab/simlink based simulation tool for this purpose.