高速永磁电机因其高效率、高功率密度、高速直驱、结构紧凑等优点，被广泛应用于航空航天、工业、国防等领域。随着高速永磁电机正在追求更高转速，对高速永磁电机的设计提出了更加严苛的要求，而转子设计是高速永磁电机设计的核心部分。由于高转速产生的离心力极易破坏永磁体，因此常采用以非导磁合金材料或复合碳纤维材料作为转子护套的表贴式永磁体转子结构。为了降低高频带来的影响，常采用实心和环形两种一对极永磁体结构。转子上不同的永磁体结构和护套材料对电机的多物理场性能有着很大影响，很难确定高性能和高机械可靠性的转子设计参数，而目前研究中缺少对不同转子结构多物理场特性的对比研究。针对上述问题，本文结合永磁体结构和护套材料对不同转子结构在多个物理场下的分布规律进行综合对比分析，更全面地探究不同转子结构的特性，为高速永磁电机的更高设计标准提供参考。具体研究内容如下：

本文以一台150000rpm的高速永磁电机为研究对象，根据高速永磁电机的设计流程和要点，确定了电机的主要尺寸，并完成了对定子铁心结构和定子绕组的设计选型。对于高速永磁电机的转子结构，结合永磁体结构和护套材料设计了六种转子设计方案，并根据电机设计理论完成了参数设计。然后基于有限元分析方法对不同转子结构的空载反电势、负载电流、气隙磁通密度等电磁特性，以及定子铁耗、定子铜耗和转子涡流损耗等损耗特性进行了对比分析。

转子的机械可靠性是高速永磁电机稳定运行的前提，本文从转子强度和模态两个方面对不同转子结构的机械特性进行了对比分析。基于转子强度分析理论，利用三维有限元方法分析了不同转子结构在不同影响因素下转子应力变化规律，总结了过盈量、温度、转速和护套厚度对不同转子结构应力的影响。针对不同转子结构在运行工况下考虑温度和转速的交叉影响进行了对比分析，确定了不同转子结构中永磁体和护套的极限运行工况，总结了不同转子结构应力校核的规律。此外，通过对不同转子结构的模态分析，对比了不同转子结构的临界转速，并探究了转子端部叶轮质量和轴承刚度对不同转子结构临界转速的影响规律。

根据电机传热理论，通过对电机定子槽内导体、定子铁心和气隙的等效导热系数以及机壳水套的对流换热系数的计算，对电机的三维模型进行简化处理，建立了不同转子结构的温度场仿真分析模型。考虑齿槽影响建立了三维流体场分析模型计算转子外表面的风摩损耗，并以风摩损耗和电磁计算的损耗作为热源，采用CFD方法对六种转子设计方案的温度场进行了仿真计算并对比分析了不同转子结构的传热特性。然后基于不同物理场性能对不同转子结构的综合特性进行了对比分析，确定了样机设计方案及参数，并通过仿真计算校验了样机性能，最后通过样机实验验证理论分析。

High-speed permanent magnet motors are widely used in aviation, industry, national defense and other fields due to their high efficiency, high power density, direct drive at high speeds, and compact structure. As high-speed permanent magnet motors are pursuing even higher rotational speeds, the design requirements have become more stringent, and rotor design has become a crucial part of high-speed permanent magnet motor design. The centrifugal force generated at high speeds can easily damage the permanent magnets, so a surface-mounted permanent magnet rotor structure with a non-magnetic alloy material or composite carbon fiber material as the rotor sleeve is often used. To reduce the impact of high frequencies, a solid and annular two-pole permanent magnet structure is commonly adopted. The different permanent magnet structures and sleeve materials on the rotor have a significant impact on the multi-physical field performance of the motor, making it difficult to determine rotor design parameters for both high performance and mechanical reliability, and currently there is a lack of research on the multi-physical field characteristics of different rotor structures. To address these issues, this thesis conducts a comprehensive comparative analysis of the distribution patterns of different rotor structures under multiple physical fields, combining the permanent magnet structure and sleeve material, to fully explore the characteristics of different rotor structures and provide reference for higher design standards of high-speed permanent magnet motors. The specific research contents are as follows:

This thesis focuses on a high-speed permanent magnet motor with a speed of 150,000 rpm. Based on the design process and key points of high-speed permanent magnet motors, the main dimensions of the motor were determined, and the stator core structure and stator winding were designed and selected. Regarding the rotor structure of the high-speed permanent magnet motor, six rotor structure design schemes were proposed, combining the permanent magnet structure and the sleeve material, and parameter design was completed based on the motor design theory. Then, using the finite element analysis method, the electromagnetic characteristics of different rotor structures such as no-load back electromotive force, load current, and air gap magnetic flux density, as well as loss characteristics such as stator loss, copper loss, and rotor eddy current loss, were compared and analyzed.

The mechanical reliability of the rotor is essential for stable operation of the high-speed permanent magnet motor. This thesis compares and analyzes the mechanical characteristics of different rotor structures in terms of strength and mode. Based on rotor strength analysis theory, the three-dimensional finite element method is used to analyze the stress variation of different rotor structures under various influencing factors, including interference fit, temperature, speed, and sleeve thickness. The cross-effect of temperature and speed on different rotor structures under operating conditions is also considered, and the ultimate operating conditions of the permanent magnet and sleeve in different rotor structures are determined, as well as the rules for stress verification of different rotor structures. In addition, the critical speeds of different rotor structures are compared through modal analysis, and the influence of rotor end wheel mass and bearing stiffness on the critical speed of different rotor structures is investigated.

Based on motor heat transfer theory, the equivalent thermal conductivity of the conductor in the stator slot, stator iron core, and air gap, as well as the convective heat transfer coefficient of the water jacket on the motor casing, are calculated. The three-dimensional model of the motor is simplified, and a temperature field simulation analysis model for different rotor structures is established. A three-dimensional fluid field analysis model is established to calculate the windage loss on the rotor outer surface, taking into account the effect of the teeth groove. The temperature field of six rotor structures is simulated and compared using the CFD method, with windage and electromagnetic losses as heat sources, and their heat transfer characteristics are analyzed. Then, the comprehensive characteristics of different rotor structures are compared and analyzed based on different physical field performances, and the design scheme and parameters of the prototype are determined. Finally, the prototype's performance is verified through simulation calculation and experimental validation.