Performance Evaluation of a Slotless Permanent Magnet Synchronous Machine with NdFeB/Ferrite Halbach Array under PWM Excitation

The performance of slotless Permanent Magnet Synchronous Machines (PMSMs) with different Halbach array rotors designed for a fixed-wing Unmanned Aerial Vehicle (UAV) application is evaluated with respect to PWM induced losses. The design analysis shows that a magnetic rotor based 620W motor with NdFeB/ferrite Halbach array that has 46 percent lower PM material cost compared to a motor with NdFeB Halbach array has comparable efficiency when operated with pulse-width modulation (PWM) at the desired switching frequencies.