The use of soft magnetic materials for improving flux weakening capabilities of axial flux PM machines

Use of axial flux machines (AFPMs) is studied in order to obtain a given value of the phase inductance, so as to use flux-weakening techniques. Slotted machines are considered, where the locking bars are made by innovative sinterized magnetic materials. A FEM model developed by the authors is used for the determination of the machine parameters: back EMF, cogging torque, load torque, axial force and inductance. A prototype machine designed and manufactured by the authors is described. The numerical tests are compared to the experimental results, allowing appreciation of the effectiveness of the proposed improvement of the machine configuration and the accuracy of the numerical algorithms.