Design and Optimization a New Spoke-Type Flux-Modulation Machine With Inverted T-Shape Permanent Magnets

This paper takes a new spoke-type flux-modulation (STFM) machine with inverted T-shape permanent magnets as the research object and proposes a multi-objective optimization design method based on air-gap flux density harmonics to improve the torque and torque ripple. The key of the proposed method is to optimize the overall torque performance by improving the contribution of main air-gap harmonics to torque and torque ripple. The working harmonic expression of the machine is firstly obtained based on the magnetomotive force (MMF) -permeance model due to the new rotor structure make the working harmonics are different from the existing flux-modulation PM machine. Then, the torques generated by the 11th and 31st air-gap harmonics and the torque ripple generated by the 29th air-gap harmonics are taken as sub-objectives. Furthermore, the response surface analysis (RSM) and the barebones multi-objective particle swarm optimization (BB_MOPSO) algorithm are combined to optimize three sub-objectives. The overall torque and torque ripple are improved due to the optimization of three sub-objectives. Moreover, the 20-slot/11-pole pair traditional model is used as a benchmark to verify the performance of the investigated machine. Finally, a prototype is manufactured and tested to verify the correctness of the theoretical analysis.