A coupled field-circuit method for thermal modeling of electrical machine

A coupled field-circuit (CFC) method for thermal modeling of electrical machine is proposed, in which some components of electrical machine are modeled with finite element (FE) method while others are modeled with lumped parameter thermal network (LPTN) method. The FE region and the thermal network are related with heat flow through borders of FE region and the temperature of nodes in thermal network. The coupling principle for static temperature distribution and transient temperature rise is elaborated in detail and 3D FE modeling is implemented to take the end winding into consideration. The proposed method is compared with LPTN method and full-order 3D FE method for the thermal modeling of a permanent magnet vernier machine. Experiment is conducted to verify the proposed method. The transient temperature rise procedure of the hot spot in winding in short time is investigated with the proposed method. The FE analysis is conducted with the software package developed with the help of finite element program generator (FEPG).