Optimal Design Study of Metal-as-Insulation HTS Synchronous Motor With Multiple Operating Points for EVs Based on Many-Objective Optimization

This paper presents an optimal design study of a high temperature superconducting (HTS) synchronous motor (HTS-SM) with metal-as-insulation (MI), taking into account multiple operating points relevant to electric vehicles (EVs). To mitigate the charging delay drawback of the no-insulation (NI) technique while retaining its self-quench-protection capability, a stainless steel MI technique is incorporated within the rotor field winding of a partial HTS-SM. Additionally, an optimal design process is proposed that considers various operating points dictated by driving profiles of EVs. The optimization process employs a recent constrained many-objective optimization algorithm (CMaO) to simultaneously handle three or more objectives with constraints. We applied the proposed process to optimize the design of partial HTS-SMs with two distinct MI thicknesses, resulting in Pareto-optimal solutions that prioritize high specific power, minimal HTS tape consumption, and high efficiency across the designated operating points. During the optimization, the finite element method was employed to accurately evaluate the motor's performance characteristics. Finally, we conducted a comprehensive analysis of the Pareto-optimal designs obtained through the optimization process.