Iron loss analysis of magnetic bearing system considering magnetic-thermal coupling

Abstract

When the magnetic bearing rotor is working, the iron loss concentration phenomenon may occur on the rotor journal, which will cause the temperature gradient on the rotor journal and thermal unbalance. In order to study the iron loss concentration phenomenon, a multi-physics simulation method considering the magnetic-thermal coupling is proposed. Using ANSYS Maxwell for modeling and finite element analysis to obtain the causes of iron loss concentration in magnetic bearing and the influence of different parameters on the size and distribution of iron loss; using COMSOL for magnetic-thermal coupling in magnetic bearing to obtain the influence of iron loss concentration on temperature distribution. The simulation results show that: because of the initial disturbance, the control effect of the magnetic bearing makes the magnetic field distribution on the circumference of the rotor journal uneven, resulting in the phenomenon of iron loss concentration; control current and bias current have significant influence on iron loss distribution, while bias current and speed have a significant influence on iron loss value; iron loss concentration will result in a temperature gradient on the rotor surface. The magnetic-thermal coupling finite element analysis is verified by the temperature rise detection experiment. It provides a theoretical basis and reference for the loss and thermal unbalance of magnetic bearing.