Analytical calculation of the switched reluctance motor's unaligned inductance

This paper develops an analytical model for the unaligned inductance of the switched reluctance motor. The analytical model is useful as long as the machine's stator and rotor poles do not overlap and its iron does not saturate. Iron saturation is almost never experienced when the rotor is in the unaligned position for practical winding currents. This paper expands on results presented previously to include the contribution to the unaligned inductance of the flux in both the stator slot and the rotor slot. The approximations that are inherent to the analytical model are stated, and a detailed development of the model is provided. Finally, the paper compares predictions of the unaligned inductance computed by the analytical model to those obtained by finite-element analysis for three different machines with different pole counts and rotor diameters.