An Improved Subdomain Model for Optimizing Electromagnetic Performance of AFPM Machines

Aiming at the problem of the time-consuming calculation of finite element method (FEM) and the poor generalizability of existing subdomain models, an improved subdomain model that takes into account the slot-opening region and introduces periodicity coefficient to reduce the size of the coefficient matrix is proposed in this paper, which can accurately predict the electromagnetic performance of axial flux permanent magnet (AFPM) machines. Meanwhile, the application range of the proposed model for any pole-slot combinations is broadened by studying the distribution law of double-layer fractional slot concentrated windings (FSCW). In addition, an evolutionary algorithm is applied to achieve rapid optimization analysis in the preliminary design, the optimized result shows a significant reduction in cogging torque and an improvement in efficiency. Finally, the reliability and effectiveness of the developed analytical model is validated by both FEM and experiments. Compared with FEM, the calculation time is reduced by 98.92% while guaranteeing computational accuracy, which greatly facilitates the design and optimization of related types of motors.