Fast Flux Maps Computation of Synchronous Reluctance Machines With and Without Permanent Magnets Assistance

This paper proposes a computational efficient and accurate hybrid analytical-finite element (FE) performance prediction methodology for synchronous reluctance (SyR) machines. The hybrid procedure consists in solving the d- and q-axis magnetic equivalent circuits in a non-linear fashion so to consider the saturation effects of both stator and rotor iron parts. The cross-coupling effects are taken into account by adjusting the analytical flux maps with the results obtained FE-simulating few operating points in the d-q current plane. The proposed approach allows to obtain an excellent estimation of the direct and quadrature axis fluxes for a wide range of operating conditions including the overload ones with a negligible computational effort when compared to a full FE analysis. The estimation accuracy has been assessed analysing a wide spectrum of SyR machine geometries featuring different stator slots and flux barriers combinations including a PM-assisted variant. A sensitivity analysis shows the trade-off between estimation accuracy and computational time while leveraging on the discretization of the airgap equivalent magnetic circuit. The proposed fast performance estimation method is finally validated against the experimental measurements carried out on a SyR machine prototype.