Electromagnetic Performance Analysis of Dual-Stator Permanent Magnet Motors Based on Hybrid Subdomain Model

Dual-stator permanent magnet motors (DSPMMs) have the advantages of fault-tolerant capability and high control flexibility due to the presence of both outer and inner stators. The DSPMM is studied in this article, whose operation performance with different stator winding connection modes is analyzed. First, a hybrid subdomain model that takes into account the influence of stator core saturation is proposed by combining the subdomain method and magnetic circuit method. The key to the model lies in using the equivalent surface current to represent the nonlinear effects of the outer and inner stator cores, which is adopted by the boundary conditions for the hybrid subdomain model. The equivalent surface current is obtained by the magnetic circuit based on the structure of stator cores. The principle and derivation process of hybrid subdomain model for DSPMM is provided in detail. The accuracy and rapidity of the proposed model are verified by comparing with the finite-element analysis (FEA) and experiment. In addition, based on the proposed hybrid subdomain model of DSPMM, the output torque, efficiency, and fault-tolerant ability with four winding connection modes are analyzed when the outer and inner stators are controlled independently or in series. The analysis results provide a reference for applying different winding structures of DSPMM to adapt different application scenarios and operation conditions.