System electromagnetic loss analysis and temperature field estimate of a magnetically suspended motor

A magnetically suspended permanent-magnet motor (MSPMM) system mainly consists of magnetic bearings (MBs), a motor and a rotor assembly. This paper focuses on the system analysis of an MSPMM used for a vacuum turbo-molecular pump (TMP). To ensure a normal levitation and rotation, characteristics of electromagnetic field of MBs and motor are studied. For MSPMM, loss is the main heat source. To ensure the safe and steady operation of MSPMM, loss of the MB and motor are calculated and analyzed by finite element method (FEM). For thermal aspects, temperature field is estimated. Based on these analyses, the system performance can be predictive. Considering the poor heat dissipation conditions in a vacuum environment, this system analysis including loss and temperature field is of great value for MSPMM design.