Research on the Airflow and Thermal Performance in a Large Forced Air-Cooled Permanent Magnet Synchronous Machine

In this paper, the airflow and temperature distribution characteristics of a 1.65MW permanent magnet synchronous machine (PMSM) adopting a totally enclosed self-circulation (TESC) axial ventilation system (AVS) are studied by numerical methods. Base on the 3-D finite volume method, the ventilation performances of the PMSM with different ventilation hole numbers on the frame and stator axial ventilation duct heights are compared to determine the optimal ventilation hole number and stator axial ventilation duct height. Then, based on the 3-D finite element method (FEM), the thermal sensitivity analysis is performed by considering the variations of the mesh and thermal conductivity of the winding insulation, and the mesh and size of the assembling clearance. The results can be benefit for identifying the most important factors affecting the accuracy of 3-D FEM thermal calculation of PMSMs. The temperature distribution of the 1.65MW PMSM with the TESC AVS is obtained in the conditions of the optimal ventilation system. At last, a 1.65MW PMSM prototype with the presented TESC AVS is developed according to the airflow and temperature calculation results, and the temperature rise test performed on the prototype validates the accuracy of the simulation results.