Topology Optimization of Asymmetric PMSM Rotor

This paper investigates the optimization of iron distribution in the rotor of a permanent magnet synchronous machine. The objective is to maximize the average torque for fixed permanent magnets positions, stator, and current feedings. To do so, a density-based algorithm is used with the adjoint variable method to compute sensitivities. It returns non-symmetric geometries, which are related to the interactions between magnets and winding fluxes, as well as the machine operating mode (motor or generator for a given rotation direction). For a given single working point, we obtain asymmetric topologies that outperform the optimized symmetric design, while the symmetric rotor topology is more multifunctional.