Design Optimization of Spoke-Type Flux-Intensifying PM Motor With Asymmetric Rotor Configuration for Improved Performance

This article explores enhancing spoke-type flux-intensifying permanent magnet (SFI-PM) motor performance by strategically placing flux barriers (FBs) in the asymmetric rotor. Integrating multi-FBs into the conventional spoke-type PM (CSPM) rotor topology elevates the d-axis inductance (L-d > L-q), intensifying flux density and improving output torque while posing challenges like increased cogging torque, torque ripple, and harmonic distortion. An asymmetric rotor design is proposed to mitigate these issues by strategically placing a higher number of FBs along the forward direction (FD) of the spoke magnet axis (q-axis). Analysis reveals that this configuration reduces torque ripple and enhances output torque. A multi-objective genetic algorithm (MOGA) is applied to optimize this asymmetric design considering mechanical constraints. The analyses are validated by manufacturing and testing a 5-kW asymmetric SFI-PM machine with a higher number of FBs along the FD of the spoke magnet axis.