Numerical simulation of a PMSM model considering saturation saliency for initial rotor position estimation

With the wide application of permanent magnet synchronous motors (PMSMs), particularly the surface mounted type, the limitations of the conventional PMSM model have become apparent, in which no saturation saliency is incorporated. As a result, the numerical simulation is not applicable for the initial rotor position estimation, which is vital for sensorless motor operation. To avoid the difficulty for developing new initial rotor position estimation techniques through the process of experimental trial and error, a new PMSM model is presented in this paper. The presented model considers both structural and saturation saliencies, enabling fast and cost-effective numerical trial and error for new initial rotor position detection methods. Unlike the constant apparent inductances in the conventional model, the nonlinear self and mutual incremental inductances in the proposed model are expressed by Fourier series and experimentally determined by a specific method to reflect the structural and saturation saliencies, which exist in both salient- and nonsalient-pole PMSMs. Based on the proposed model and the measured inductance patterns, an initial rotor position estimation scheme is numerically simulated and experimentally tested.