【目的】为了提升永磁调速器(PMASD)的转矩密度，本文提出了一种复合磁通型鼠笼结构PMASD，并对其进行了电磁设计与电磁特性分析。【方法】首先，对所提PMASD的结构和原理进行了简要介绍，并基于等效磁路法建立了PMASD理论模型；然后，基于有限元法建立了PMASD仿真模型，研究了永磁体极弧系数、永磁体厚度和极对数等关键结构参数对PMASD气隙磁场、转矩及转矩脉动的影响，并分析了L型导条截面积对PMASD损耗特性与转矩特性的影响；最后，分析了不同鼠笼导体转子平移距离下的转矩特性及调速特性。【结果】极弧系数为0.8时，PMASD气隙磁密波形更接近正弦波，转矩脉动较小；随着永磁体厚度的增加，气隙磁密基波幅值增加，增幅减小；永磁体厚度和极弧系数的合理配合，可以提升基波占比；随着极对数的增加，在低转差速度范围内，PMASD转矩输出能力先增再降，且最高转矩对应的转差速度呈先增再减趋势；随着导条截面积的增加，导条电阻减小，鼠笼转子铜耗降低；随着平移距离的增加，转矩与铜耗整体呈下降趋势，但是下降速率逐渐降低。【结论】所提复合磁通型鼠笼结构提升了PMASD的转矩输出能力和转矩密度，具有良好的调速特性和导热能力

[Objective] To enhance the torque density of permanent magnet adjustable speed drive (PMASD), this paper proposes a composite flux PMASD with squirrel-cage structure, and conducts its electromagnetic design and electromagnetic characteristic analysis. [Methods] Firstly, a brief introduction to the structure and principle of the proposed PMASD was provided, and the theoretical model of PMASD was established based on the equivalent magnetic circuit method. Secondly, the PMASD simulation model was established based on the finite element method. The influence of key structural parameters such as the pole-arc coefficient, thickness and the pole-pairs of permanent magnets on the air-gap magnetic field, torque and torque ripple of the PMASD were studied. And the influence of the cross-sectional area of L-shaped conductor on the loss and torque characteristics of the PMASD were also analyzed. Finally, the torque characteristic and speed regulation characteristic at different shifting distances of the squirrel-cage rotor were analyzed. [Results] When the pole-arc coefficient was 0.8, the air gap flux density waveform of the PMASD was closer to a sine wave, and the torque ripple was relatively small. As the thickness of the permanent magnet increases, the amplitude of the fundamental wave of the air gap flux density was increased, with the growth rate gradually decreasing. A reasonable combination of permanent magnet thickness and pole-arc coefficient could improve the fundamental wave proportion. As the number of pole-pairs increased, within the low slip speed range, the PMASD torque output capacity was first enhanced and then decreased. Meanwhile, the slip speed corresponding to the maximum torque showed a trend of first increasing and then decreasing. As the cross-sectional area of the conductor bar increased, the resistance of the conductor bar was reduced, and the copper loss of the squirrel-cage rotor was decreased. With the increased of shifting distances, the torque and copper loss were generally reduced, but the reduction rate was gradually decreased. [Conclusion] The proposed composite flux squirrel-cage structure enhances the torque output capability and torque density of the PMASD, offering excellent speed regulation characteristics and thermal conductivity.

国家自然科学基金(52107048,52307040)