Multi-Objective Electromagnetic Topology Optimization of a Partial-Superconducting Direct-Drive Generator for Wind Turbines

This paper proposes a topology optimization method for the electromagnetic design of a high-temperature superconducting (HTS) machine. The primary objective is to maximize torque density. The secondary objective aims to regulate the average flux density in the stator core to knee point of material BH curve. It prevents saturation and promotes high material utilization. Multimaterial topology optimization method is researched. A multimaterial topology optimization approach is employed, utilizing a density-based method to represent the rotor structure comprising HTS tapes, iron, and air. The Solid Isotropic Material with Penalization (SIMP) interpolation scheme is applied to suppress intermediate densities. Throughout the optimization process, the critical current of the HTS tapes is dynamically evaluated. The stator is designed with shape optimization method which is coupled with the topology optimization method. The average flux density of stator core is calculated with parameter optimization method. Simulation results validate the proposed design, achieving an active weight torque density of 140 Nm/kg and a stator core flux density of 1.78 T. The total computation time is reduced, ranging from several to tens of hours.