Analytical nonlinear model for permanent magnet synchronous machine incorporating saturation saliencies

This paper investigates the nonlinear model of the permanent magnet synchronous machines (PMSMs). In order to incorporate the structural and saturation saliencies, two parameters are defined to indicate the saturation ratios. An analytical model is derived and the inductance matrix is expressed in both stationary and rotating reference frames, respectively. An incremental inductance measure system is established, on which a real PMSM is tested and numerically simulated. The nonlinear inductance matrix is deduced and expressed by a nonlinear function, regressed from the experimental collected data. Based on the magnetic parameters observed from the prototype, the estimated inductance curves are compared with the experimentally measured curves. Finite Element Method (FEM) is also applied to verify the developed mathematic model. Finally, simulations and experiments are carried out to verify the proposed model. The results show that the proposed method can be applied to analytically express the machine nonlinearity.