Electromagnetic and Thermal Analysis of 225 kW High-Speed PMSM for Centrifugal Blower Applications

In order to make centrifugal blowers environmentally friendly, machines with a lighter weight and a more compact size are required. Thus, the axial length of the machine needs to be minimized within the diameter limit. However, in the design methodology, losses and thermal study become very significant; thus, losses increase significantly to achieve the desired output power when the volume is excessively reduced. Moreover, due to the machine’s compact size, heat is concentrated rapidly without adequate cooling. It might lead to a temperature rise of the critical part of the machine above the safe limit, such as winding, thereby affecting its lifespan. This study considers the 225 kW high-speed permanent magnet synchronous machine (HSPMSM) with the forced air cooling axial ventilation system (FACAVS) used in centrifugal blower applications. Firstly, four different analytical models (A2–A5) in the electromagnetic analysis are derived by minimizing the initial machine’s (A1) axial length to achieve a lighter weight and more compact size with better electromagnetic performance. The best among analytical models is chosen as the A4 model with a lighter weight and a more compact structure in addition to higher torque density than A1, A2, and A3 models, and higher efficiency than A1, A2, A3, and A5 models by HSPMSM’s, optimal geometric design, and optimal material choice, respectively. Secondly, LPTN is designed to predict the entire analytical model’s thermal behavior in the thermal analysis. Investigation shows that winding temperature rises from the A4 model is maintained below winding insulation by the determined optimal axial ventilation parameters from the sensitivity analysis. Finally, different analytical models are prototyped and tested. The comparisons between predicted electromagnetic performance, winding temperature rise, and test results were carried out, and the results were found to agree with each other consistently.