Estimation of PM Temperature Distribution for Flux-Switching PM Machine by Synergy of Lumped-Parameter and Analytical Thermal Models

This paper proposes an analytical thermal model for permanent magnets (PMs) in the flux-switching PM machine to estimate PM temperature distribution and local hotspot temperature. The analytical thermal model is obtained by solving Poisson's equation with inhomogeneous boundary conditions, where the non-uniform PM loss distribution is also considered. Furthermore, it can be synergized with the conventional lumped-parameter thermal model accounting for the load-dependent thermal conditions. It is shown that the maximum PM temperature will be concentrated adjacent to the airgap due to convection heat transfer of airgap and local PM loss concentrated caused by the skin effect. The electromagnetic-thermal coupled finite element model is used for validation.