: This study investigates the performance improvement of a high-speed interior permanent magnet synchronous motor (IPMSM) for aerospace propulsion by
applying a high–grade magnetic material. In aerospace propulsion systems, efficiency and weight are key design indicators, and simultaneously achieving improvements in both remains a major technical challenge due to the strong coupling between electromagnetic loading, thermal constraints, and structural limitations under high-speed operation. The purpose of this study is to verify the feasibility of enhancing IPMSM efficiency and reducing the overall weight by employing a highgrade magnetic material with superior magnetic properties. Three standard-rated motors were initially designed using 35PN230 electrical steel as the baseline model, and their electromagnetic performance was evaluated through finite element analysis (FEA). The rated power and speed of each
model were selected based on representative operating conditions of aerospace propulsion systems to ensure practical relevance. Subsequently, the stator core material was replaced with Hiperco 50, and the effects of this material substitution on flux distribution, saturation behavior, and loss characteristics were analyzed. By utilizing the higher saturation flux density of Fe–Co electrical steel, the stator core was redesigned to operate under higher magnetic loading conditions, enabling a reduction in stator dimensions while maintaining stable electromagnetic performance. Comparative results showed that the model using Hiperco 50 exhibited higher efficiency and reduced core mass compared with the conventional design, while maintaining almost the same average torque. On average, the full application of Fe–Co resulted in approximately 0.9% improvement in efficiency and about 21.2% reduction in motor weight. In addition, to address the high material cost of Fe–Co electrical steel, a separated stator configuration was considered, in which Fe–Co was applied only to the stator teeth region while the
stator back-yoke remained composed of Fe–Si electrical steel. This approach provided an average efficiency improvement of approximately 0.5% and a weight reduction of about 13.5% compared to the baseline model, while reducing the required amount of Fe–Co material. These results confirm that the application of Fe–Co electrical steel provides an effective means to achieve high-efficiency and lightweight design in aerospace propulsion motors, and that selective material application can offer a practical balance between performance improvement and material cost.