Design Optimization of an Outer Rotor PMSM for Electrical fixed-wing UAV Application Considering the Torque/RPM Working Cycle

In this paper, a novel methodology for the design optimization of permanent magnet synchronous machines (PMSM) is presented. It is applied to an outer rotor machine for an unmanned aerial vehicle (UAV). The study shows how, considering all points (up to several thousands) of a working cycle torque/RPM, it is possible to optimize both geometry and control strategy, with the objective of weight and losses minimization while keeping a reduced computational time. With this kind of applications, the working points can have a big variation, which requires a specific method to avoid oversizing and to control multiple constraints in the same time. Hence, the temporal thermal variation is calculated, taking into account the transient. The magnetic saturation, geometrical and electrical constraints are also considered along the working cycle. The electromagnetic model is presented and validated by finite element analysis (FEA).