An Enhanced Analytical Calculation of the Phase Inductance of Switched Reluctance Machines

Accurate prediction of the phase inductance of switched reluctance machines (SRMs) is of crucial importance at the design stage because it is a key parameter to estimate the performance indices, such as the torque and loss. Instead of using the popular but time-consuming finite-element analysis (FEA) or the methods that require prior knowledge of magnetic fields from an FEA, such as function approximation and flux path methods, this paper proposes a novel fast and accurate analytical approach to determine the phase inductance of an SRM by solving the partial differential equations of magnetic potentials based on Maxwell's equations. In particular, an enhancement of the accuracy of the analytical model is accomplished by applying conformal mappings that deal with the non-radial/non-peripheral geometric structures when calculating the air-region permeance parameters. Moreover, a magnetic circuit network is applied to account for the steel saturation effects. The close agreement between the results of the proposed analytical method, FEAs and experimental measurements validate the analysis.