Modeling of Six-phase Permanent Magnet Synchronous Motor

Abstract

For proper utilization of six-phase permanent magnet synchronous motor (PMSM) it is necessary to have a precise dynamic model that truly represents it. However, dynamic models of the existing six-phase PMSM, in general, were not precisely established. In this thesis a new mathematical modeling for both surface mounted six-phase permanent magnet synchronous motor (SPMSM) and interior permanent magnet synchronous motor (IPMSM) are proposed. Accurate representation of six-phase PMSM flux model through proper analysis of saliency in IPMSM is pursued. The proposed model utilizes two reference frames. First, coordinate transformation is used to transform six-phase PMSM flux model in abcxyz-frame into two stationary and two synchronous rotating frames. Then, differentiating the flux models respective voltage equations in stationary and rotating frames are obtained. The torque equation is derived using the cross product between fluxes and currents of respective reference frames. Combining the obtained flux model and Finite element method (FEM), a new inductance calculation method is also developed. FEM was used to justify the correctness of the flux model. Simulation of dynamic performance of the proposed model by Matlab/Simulink showed the model is well-founded. Finally, experimental verification was performed using a 100 kW six-phase IPMSM which supported the validity of the proposed model.