Modelling of surface mounted PM machines incorporating saturation saliency and frequency variation

In this paper a comprehensive magnetic model is developed for a surface mounted permanent magnet synchronous machine (SPMSM) considering both the structural and the saturation saliencies to enable the numerical simulation of new rotor position detection algorithms. With an identifiable parameter matrix, a numerical nonlinear inductance model is proposed, in which the rotor position and the stator current are taken as two independent variables. Additionally, the stator current frequency is taken as another factor of the inductances and the inductances for different frequencies are investigated. After experimentally identifying out all the parameters, a nonlinear mathematic model of SPMSM is built up based on the new magnetic inductance function. Finite element method (FEM) based calculation and simulation results are used to verify the proposed nonlinear magnetic model.