变频器供电永磁同步电动机电磁振动关键基础问题研究

The inverter-fed permanent magnet synchronous motors (PMSMs) have become extensively used in high performance servo and speed control systems. However, the electromagnetic force components are more complicated as a result of the rich harmonics in stator currents, and the reduction of electromagnetic vibration also becomes much more difficult due to the changing of motor speed, inverter output frequency and the frequency of electromagnetic force within wide ranges. The mismatch among the control parameters of inverter, motor parameters and the vibration characteristics of rotor shaft system may cause the electromagnetic oscillation and resonance, which results in the decrease of control precision and system stability. In serious situation, the rotor shaft can be fatigue damaged and the operation reliability is reduced.. To effectively reduce the electromagnetic vibration of the inverter-fed PMSMs, this project will study the mapping relation between electromagnetic force wave and the parameters of inverter-motor system under different operation conditions, and an accurate and efficient calculating method based on the combination of analytical method and finite element method is to be proposed to calculate the electromagnetic force wave taking into consideration the influences of rich current harmonics, complex structural parameters and different control strategies. The effects of the complex structural parameters on motor mode and the corresponding equivalent method will be further studied. The methods to calculate the tangential, radial and axial mode can be established based on the equivalence of complex structure to regular structure. Then the coincidence rule of frequency between electromagnetic force waves and natural vibration within a wide frequency range for inverter-fed PMSM will be studied. The collaborative mechanism among the control parameters of inverter, motor parameters and vibration characteristics of rotor shaft system, and the production mechanism and stability criterion of electromagnetic-mechanical resonance are to be further analyzed. Finally, a collaborative design method, which takes the electromagnetic force waves, multidimensional modal coupling and electromagnetic-mechanical resonance into consideration, will be established to lay a theoretic foundation for the reduction of vibration and noise for the inverter-fed PMSMs.

本项目拟针对变频器供电永磁同步电动机转速范围宽、电磁力来源复杂、易发生电磁—机械共振、电磁振动削弱困难的特点，研究不同工况下电磁力波与电机—变频器系统参数间的映射规律，建立能准确高效计算包括幅值、转速、频率和相位的电磁力波计算方法，计算计及丰富电流谐波、复杂结构参数和不同控制策略影响的各电磁力波；深入研究复杂结构参数对电机模态的影响及其等效方法，进而建立计及复杂结构的切向、径向和轴向模态计算方法；研究变频器供电永磁同步电动机在宽频率范围下定转子电磁力波频率和电机固有振动频率的重合规律，深入分析变频器控制参数、电机参数和转子轴系振动特性的协同作用机理，以及电磁—机械共振的产生机制和稳定性判据；以削弱电磁振动为根本目标，建立一套综合考虑电机激振力波、多维模态耦合和电磁—机械共振的协同设计方法，为削弱变频器供电永磁同步电动机电磁振动奠定坚实理论基础。

变频器供电永磁同步电机因具有良好的性能在高性能调速领域获得了广泛应用。在一些高速大功率的应用场合，电机的电磁振动问题非常突出，是亟待重点解决的问题之一。为此，本项目对变频器供电永磁同步电动机电磁振动这一关键基础问题展开系统的研究，主要研究工作如下：.1）表贴式永磁同步电动机电磁力波快速准确计算方法的建立。提出了子域法与磁动势-磁导法相结合的电磁力波快速准确计算方法，给出包括幅值、阶次、频率、相位的完整的电磁力波表达式；详细分析了定转子结构参数和电流谐波对电磁力波的影响。.2）内置式永磁同步电机气隙磁场及电磁力波解析计算方法的建立。针对复杂的内置式转子结构，提出了全新的转子子域划分方法，建立了内置式永磁同步电机气隙磁场的解析计算模型；基于提出的解析计算模型和磁动势-磁导法，给出了内置式永磁同步电机径向电磁力波的完整的表达式。.3）定子固有频率的快速准确计算方法的建立。针对现有固有频率解析计算方法精度低的问题，本项目给出了定子各部分的准确等效模型和各向异性材料参数的确定方法，基于能量法推导了定子自由振动的特征方程，提出了包括绕组和机壳在内的定子固有频率快速准确计算方法。.4）电磁振动快速计算方法的建立。结合提出的电磁力波和定子固有频率快速准确计算方法，建立了基于线性叠加原理的电磁振动计算方法；以削弱电磁振动为根本目标，提出了定子开辅助槽、永磁体分段斜极等电磁振动综合削弱措施。.5）永磁同步电机电磁-机械振动解析模型的建立。建立包括控制系统、电机本体、机械负载的电磁-解析耦合分析模型，深入分析了变速调节、负载突变等对电机扭振的影响；提出了转子扭振的削弱措施，并进行了样机研制和实验验证。.本项目建立了变频器供电永磁同步电动机在复杂因素影响下的电磁力波和定子固有频率完整的分析和计算体系，给出了通用的电磁振动削弱措施。本项目的完成，对于保证降低电磁振动和提高系统的工作可靠性，具有重要的科学价值。