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In order to improve the performance (low torque ripple, low suspension ripple, and high power factor) of the permanent magnet assisted bearingless synchronous reluctance motor (PMa-BSynRM), the multiobjective optimal design based on fast nondominated sorting genetic algorithm (NSGA-Ⅱ) of PMa-BSynRM rotor topology is investigated in this article. First, the structure and operation principle of the PMa-BSynRM are introduced. Second, the initial rotor design that gives optimizer the ability to produce a variety of barrier shapes and the comprehensive sensitive analysis that evaluates the influence of each design variable on optimization objectives are presented. Third, the optimal design is selected from the Pareto front, which is generated by NSGA-Ⅱ, and validated by finite-element analysis. The simulation results confirm that the torque and suspension force capacity of optimal motor are improved significantly in comparison with initial design, whereas the value of power factor reaches 0.81. Finally, the optimal prototype motor is manufactured, and experimental results confirm the validity and superiority of the optimized design. [ABSTRACT FROM AUTHOR]

The traditional bearingless synchronous reluctance motor (BSynRM) with salient pole rotor has some drawbacks such as high suspension force ripple, low torque density and low power factor. To overcome the above shortcomings, the permanent-magnet-assisted bearingless synchronous reluctance motor (PMa-BSynRM) is proposed. In this paper, two types of PMa-BSynRM rotors with the same number of permanent magnets but different magnetic barrier structures are designed. A traditional BSynRM with a salient pole rotor is introduced, and the electromagnetic and vibration characteristics of the three BSynRM are analyzed and compared. Firstly, the rotor structures of the two PMa-BSynRMs are designed, and the operation principle of the BSynRM is introduced. Secondly, electromagnetic characteristics of the three motors are analyzed and compared in detail using FEA software. Thirdly, the vibration analysis of the three motors is carried out. Finally, the experimental prototype platforms are built. The FEA and experimental results verify that the designed PMa-BSynRM can improve the power factor and torque density of traditional BSynRMs, and the most superior BSynRM among the three is identified. [ABSTRACT FROM AUTHOR]