Thermal Analysis of a Permanent Magnet Assisted Excitation Motor

This paper presents the electro-magnetic, thermal and fluid dynamical analysis of a promising hybrid excitation permanent magnet motor. The hybrid excitation permanent magnet motor is a synchronous motor characterized by a rotor including both permanent magnets and excitation windings. Thus, it is possible an active change of the magnetic field by the excitation current control. 2-D thermal-fluid dynamic numerical simulations are carried out to study the heat exchange of a hybrid permanent magnet-salient pole motor. The air turbulent motion is analysed to understand how the heat transfer between salient pole surfaces and air takes place. Heat transfer coefficients are computed for different rotor speeds. Therefore, to carry out a simple and fast thermal analysis, heat transfer coefficients evaluated can be employed in a lumped parameters thermal network of the motor.