车用内置切向式分数槽永磁同步电机损耗解析建模与效率优化研究

Fractional-slot permanent magnet synchronous motor (FS-PMSM) has a brilliant prospect in electric vehicle application, since its advantages of short winding end, small volume, easy processing, and so on. But its armature magnetic field contains high-amplitude sub-harmonic components. Sub-harmonic fields would induce eddy current losses in rotor, which further cause temperature rise and demagnetization of magnets in high speed. This is already become the development bottleneck of FS-PMSM because of the potential security problem. A fractional-slot interior permanent magnet synchronous motor (FS-IPMSM) with multi-layer armature windings and segmented tangential structure is presented and studied in this project. Analytical modeling method of IPMSM will be studied with the considering of iron local saturation. The model can calculate the magnetic field and losses quickly and accurately. Furthermore, copper loss, iron loss and PM eddy current loss model will be built based on the analytical model of magnetic field. Loss suppression methods will be studied by investigating the influence of motor parameters on the magnetic field and losses. Particle swarm optimization (PSO) algorithm will be employed, combining parameters decoupled methods, to optimize the motor structure and improve its efficiency. Considering the change of resistance and inductance, efficiency optimization control strategy over full-speed range for electric vehicles will be studied based on model protective current control method (MPCC) to improve the operation efficiency of the motor. Based on the above works, a firm theoretical and practical foundation is established to improve the performances of FS-PMSM. This project has important research value and practical significance for improving the design level of electric vehicle drive motor in China.

分数槽永磁同步电机因其绕组端部短、体积小、易加工等优点，在电动汽车领域具有较好的应用前景。但其电枢磁场中存在高幅值的次谐波分量，高速运行时会在转子上感应出涡流损耗，导致永磁体温升和退磁，存在安全隐患，成为限制其发展的瓶颈。针对该问题，本项目提出一种定子采用多层集中绕组、转子采用内置切向式磁极的电机结构，研究考虑铁心局部饱和的子域解析建模方法，解决内置式电机磁场准确建模的难题；基于磁场模型进一步建立铜耗、铁耗和永磁体涡流损耗的损耗解析模型，研究电机参数对磁场和损耗的影响规律，探索损耗综合抑制方法，并将参数解耦与粒子群优化算法相结合对电机结构进行优化，提高电机效率；研究电机阻感参数随运行工况的变化规律，基于模型预测电流控制方法提出全速域内电机效率优化控制策略，综合提高电机的整体运行效率。本项目的工作将为改善分数槽永磁同步电机的高速性能提供理论基础，为我国电动汽车驱动电机的研究提供一种新思路。

面对庞大的石油能源消耗和温室气体排放，新能源电动汽车产业逐渐成为国家重点关注的领域。分数槽集中绕组永磁同步电机（Fractional-slot concentrated-winding permanent magnet synchronous machine，FSCW-PMSM）具有绕组端部短、槽利用率高、定子铜耗低、效率高、转矩密度大及齿槽转矩低等优点，近些年在电动汽车领域逐渐成为研究热点。然而FSCW-PMSM电枢磁场中含有高幅值的空间谐波分量，其旋转速度与转子不同，当电机高速运行时，会在永磁体中感应出较大的涡流损耗。而且当电机由控制器驱动时，电机电枢电流含高频时间谐波分量，时空谐波磁场会增加转子损耗，使电机转子发热，严重时甚至会导致永磁体退磁、损坏电机。.针对现有问题，本项目首先提出了一种定子采用多层集中绕组、转子采用内置切向式磁极的FSCW-PMSM，研究了考虑铁心局部饱和的内置式永磁同步电机子域解析建模方法，解决磁场和损耗快速、准确计算的难题。并以四台绕组结构不同的10极12槽永磁电机为例，利用有限元仿真验证了损耗模型的精确性。基于该损耗模型，本项目推导了谐波涡流损耗随绕组相数和层数的变化规律，并使用磁动势从机理上分析该规律。进一步，为解决FSCW-PMSM电枢绕组磁动势中存在高幅值低次谐波这一难题，对多层绕组采用星-三角(Y-△)接法的FSCW-PMSM进行理论分析，推导出适用于任意匝数比例、机械角度差的谐波磁动势计算方法，并由三相电机推广到m相FSCW-PMSM上。将四层绕组结构与绕组偏移技术相结合，定子上提出了一种新型的低谐波双三相10极24槽绕组拓扑结构。转子结构方面，本项目对比了表贴式、径向式、切向式、“V”形四种结构的10极12槽FSCW-PMSM电磁性能。结果表明，当永磁电机定子侧采用四层Y-△接法、转子侧为切向式拓扑结构时，不仅可以减少永磁体使用量、节约电机的制造成本，而且还可以提高电机性能。最后，本项目提出了一种逆变器与FSCW-PMSM联合系统中电机损耗谐波特性的分析方法，并通过实验验证分析了该结论的有效性。本项目的工作将为善FSCW-PMSM高速性能提供理论基础，为我国电动汽车驱动电机的研究提供一种新思路。