General Analytical Magnetic Model for Partitioned-Stator Flux-Reversal Machines With Four Types of Magnetization Patterns

A partitioned stator-flux reversal (FR) permanent magnet machine (PS-FRPMM) is a new combination of a stator PM machine and a magnetically geared machine and has the specifications of both machines in terms of robust structure and torque density. In this paper, a comprehensive 2-D analytical model is developed for PS-FRPMM based on subdomain technique. The presented model has the capability to accurately and quickly investigate the effects of design parameters on the machine performance. The 2-D analytical model is evaluated on two case studies with 12 stator teeth and 10 rotor poles, and 18 stator teeth and 13 rotor poles, with four different magnetization patterns. The influences of various design parameters such as the rotor slot width, slot opening width, and the segment ratio of the PMs in the two-segment magnetization pattern have been investigated on the quantities, such as the instantaneous torque, torque ripple, unbalanced magnetic force (UMF), and electromotive force (EMF). For evaluating the presented analytical model, the 2-D finite element method (FEM) with and without saturation effects has been used. The comparative study between the analytical and numerical models shows good agreement. Finally, a 3-D FEM has been used, and the results of the 2-D analytical model and 3-D FEM are compared in terms of the accuracy and computational time. The results show that the presented model has lower computational time compared to the 2-D and 3-D FEM, while its accuracy is acceptable under different circumstances, such as saturation.