Modeling of Surface-mounted Permanent Magnet Synchronous Motors with Inner and Outer Rotor Types

A surface-mounted permanent magnet synchronous motor (SPMSM) is an electric machine applied widely in the fields of electric vehicles (EVs) and electrical drives due to good characteristics such as  high power density, lower mass, high efficiency and lower torque of inertia. For the SPMSM, there are two types of  SPMSM, i.e., the inner rotor SPMSM and outer rotor SPMSM. In order to analyze, compute and compare advantages and disadvantages of these two motor types,  this research proposes an analytical model in detail to calculate and design the electromagnetic parameters and thermal characteristics of the SPMSM with both inner and outer rotor configurations. Subsequently, a finite element method is developed to validate output parameters obtained from the analytical model. Simulation results also indicate the performance of both types of motors. However, the inner rotor SPMSM has advantages in terms of high speed and low temperature, while the outer rotor SPMSM has higher torque and stability but it operates at a higher temperature.