Slotless lightweight motor for drone applications

This paper proposes a slotless, lightweight permanent magnet (PM) motor for drone applications. This research analyzes the steps through FEA to achieve the torque speed profile required for drone applications with optimum pole count for the base speed. A comparison on slotless vs slotted stators is presented. In addition, an optimization using halbach configuration proves to give a superior design over conventional rotor designs. Finally, the analysis leads to a slotless stator with halbach PM configuration in the rotor for a 4 kW system achieving high power density, very low cogging torque and torque ripple, sinusoidal BEMF, and good system efficiency. The resulting low inductance (μH range) of the proposed machine opens up the opportunity of using wide band gap devices as the enabling technology.