Flux‐adjusting characteristic analysis and optimization design of variable‐leakage‐flux interior permanent magnet motor

Abstract

In this paper, a novel variable-leakage-flux interior permanent magnet (VLF-IPM) motor is proposed, which is a kind of mechanical flux-adjusting PM motor. The VLF-IPM motor can obtain the advantages of the IPM motor and overcome the difficulty to adjust PM airgap flux by locating a self-activating device that is introduced in this paper on the rotor. The effect of the flux barriers on the flux leakage circuit is analysed by establishing a rotor parametric model to clarify the influence of flux barriers of the VLF-IPM motor on flux-adjusting performance. Then, the electromagnetic performance of VLF-IPM motors with different volume ratios of cylindrical permanent magnets (CPMs) and rectangular permanent magnets (RPMs) are compared by using the finite element analysis (FEA) method, and the experiment results show that VLF-IPM motor with characteristics of 0 < κrc < 1 has more advantages comprehensively. Moreover, a multi-objective optimization process is adopted based on sensitivity analysis which can reflect the influences of geometric parameters on the optimization objectives including average torque, torque ripple and cogging torque. Then, the Non-dominated Sorting Genetic Algorithm II(NSGA-II) is utilised to determine the optimal model. Finally, a prototype is manufactured and tested, and the effectiveness of the novel VLF-IPM motor and the self-activating device are verified by the simulation and experiments.