Quasi-3-D Nonlinear Analytical Modeling of Magnetic Field in Axial-Flux Switched Reluctance Motors

Analytical modeling (AM) of the magnetic field for axial-flux switched reluctance motors (AFSRMs), considering 3-D features and nonlinear saturation effects, remains to be a knotty problem. This article proposes a quasi-3-D nonlinear AM method to predict magnetic field distributions and electromagnetic performances of an AFSRM. First, the harmonic modeling (HM) technique is applied to obtain the spatiotemporal distribution characteristics of the axial and tangential magnetic flux density at the mean radius. Second, the nonlinearity of the soft magnetic material in teeth is considered by an adaptive convergence rate algorithm. Finally, a radial dependence function is formulated to extend the solution of the annular Section to any point in the 3-D space of the AFSRM. To confirm the accuracy of the proposed method, the analytical solutions of magnetic flux density and electromagnetic torque have been compared with FEM simulation results. Meanwhile, an additional validation has been done for the stability of this nonlinear AM method under severe saturation conditions. Finally, the reasonable selection of the harmonic truncation order number has been discussed to reach a good balance between accuracy and time cost. The quasi-3-D nonlinear AM method can consider the curvature and edge effect, as well as the saturation effect effectively, which is suitable for performance predictions and parametric studies of AFSRMs.