Two-level Design Optimization of AC Machines with DC Stator Excitation and Minimal Torque Ripple using Reluctance Rotor Profile Shaping

Torque ripple mitigation in electric machines is important for a smooth and stable operation, minimize mechanical vibrations, and enhance the overall performance. In this paper, a novel two-level optimization method is proposed for the design of synchronous flux-switching and hybrid excitation machines with an innovative multi-point spline shaping method to minimize the torque ripple. This study uses models that are validated by experimental tests from a prototype with similar topology, and exemplifies the aforementioned optimization process on a 28 pole machine. The analysis results indicate that the torque ripple can be substantially reduced with improved electromagnetic torque of the electric machine, and the combination of force analysis and the multi-point spline shaping ensure the manufacturability of the machine.