Minimization of cogging torque in permanent magnet machines using the topological gradient and adjoint sensitivity in multi-objective design

The paper presents an application of the topological derivative and continuum sensitivity analysis for the optimal design of the permanent magnet excited machines with the adjustable excitation. In our work we applied a topological optimization in order to find a general shape of rotor poles consisted of an iron and magnet part. An essential advantage of the proposed method is its numerical effectiveness. In order to verify results, three-dimensional models were developed and thoroughly analyzed. As presented in the comparative analysis of 3D results, the applied method lead to the significant reduction of both, the cogging torque and a level of higher harmonics in the voltage induced in the armature windings.