Topology optimization of switched reluctance motors for the desired torque profile

This paper presents the design optimization of switched reluctance motors (SRMs). The design goals are high average torque, low torque ripple and low mass under the constrained phase current of SRMs. To achieve these goals, we design not only the geometries of SRMs using topology optimization, but also voltage on-off angles. The performance analysis of SRMs is carried out to predict the torque profile. Fourier series expansion is used to obtain the explicit expression of inductance curves, which allows us to perform the analytical design sensitivity analysis of the torque profile. The optimization problem is solved using the sequential linear programming (SLP) method. In the optimized geometry, the arc lengths of poles are increased with the notched shape near airgap, and the holes inside the rotor are created. In addition, the mechanical characteristics of the optimized SRM are investigated using the modal and thermal analysis by MSC/NASTRAN.