Novel Asymmetric IPM Rotor Design Using Cascaded Multiphysics Topology Optimization

Abstract

Sustainable motor design is crucial for improving energy efficiency and reducing material consumption. This paper introduces a novel asymmetric interior permanent magnet (IPM) rotor design using topology optimization (TO). The study employs a two-stage TO approach to design IPM rotor. In the first stage, a multi-objective electromagnetic TO is conducted to enhance the average torque and reduce the mass of the magnetically active rotor zone. In the second stage, structural TO is performed to minimize the mass of the magnetically inactive rotor zone while maintaining mechanical integrity, ensuring the rotor withstands operational mechanical stresses. The asymmetric topology-optimized IPM (ATO-IPM) machine is analyzed and benchmarked against the conventional IPM design and the symmetric topology-optimized IPM (STO-IPM) design. The results indicate that the asymmetric flux barriers enhance the torque performance. The ATO-IPM design offers significantly more efficient utilization of permanent magnets (PMs) and improved torque density by approximately 13.3% compared to the conventional IPM motor. Moreover, ATO-IPM design supports the advancement of sustainability by improving efficiency by 2.3% compared to conventional design. Furthermore, ATO-IPM designs save about 46.7% of the amount of silicon steel of the conventional topology.