Magnetic Saturation in Semi-Analytical Harmonic Modeling for Electric Machine Analysis

A semi-analytical method based on the harmonic modeling (HM) technique is presented for the analysis of the magneto-static field distribution in the slotted structure of rotating electric machines. In contrast to the existing literature, the proposed model does not require the assumption of infinite tooth permeability, material property homogenization, or a hybrid modeling approach. In fact, the permeability variation in the slotted machine parts is embedded directly into the magnetostatic field solution. Currently, only linear soft-magnetic materials with finite permeability are considered. However, non-linear materials could be considered iteratively, and therefore the proposed model presents a first step toward including the magnetic saturation effects into HM. To validate the presented method, semi-analytical models are implemented for two benchmark topologies with slotted rotors. Magnetic field calculations are performed for two different values of linear rotor tooth permeability and compared to finite-element analysis predictions. The results show that a very good agreement is obtained.