A Performance Comparison of Radial Flux SPM Machine and YASA Machine

The axial flux yokeless and segment armature (YASA) machine and the radial flux surface-mounted permanent magnet (SPM) machine are widely used in the electric aviation field as two kinds of high-power density motor topologies. This paper analyzes the effect of key geometrical parameters including air-gap area on the performance of the machine. Both motors' torque density, overload capacity, and efficiency are compared by the magnet equivalent circuit (MEC) method and finite element analysis (FEA) method. The results show that the YSAS machine has a smaller volume and higher overload capacity. The weight and efficiency of the two motors have their advantages, which depend on the size and working condition of the motor.