低速大扭矩永磁同步电动机的转矩提升

Torque increase of permanent magnet synchronous motor with low-speed and high-torque

针对永磁同步电动机的转矩提升问题,以一台48槽40极的160 kW内置切向式直驱用低速大扭矩永磁同步电机为研究对象,分别以定子不等齿宽削弱齿槽转矩和转子轭部开孔增大输出转矩来提升电机的转矩特性。首先给出电动机的定子齿槽分组和偏移方式以实现定子不等齿宽,对其气隙磁密进行傅里叶分解,推导了不等齿宽下齿槽转矩的解析式,得到不等齿宽对齿槽转矩的影响规律和削弱效果随定子齿槽偏移角度的变化规律,给出能够有效抑制齿槽转矩的最佳偏移角度,并经有限元法予以验证;其次研究转子轭部开孔时电动机的输出转矩,进一步分析孔的形状、尺寸和数量对转矩的影响规律,仿真分析表明转子轭部开孔可适当增大输出转矩,并给出了最佳的孔形、数量及其尺寸。

Due to the problem of torque increase of permanent magnet synchronous motor, a 48-slot, 40-pole, 160 kW internal tangential direct drive permanent magnet synchronous motor with low-speed and large-torque is taken as the research object. The torque characteristics of the motor are improved by reducing the cogging torque and increasing the output torque. The unequal tooth width of stator is used to weaken the cogging torque and the rotor yoke hole is used to increase the output torque. Firstly, the unequal tooth widths of stator was obtained according to method of stator tooth slot grouping and deflection proposed in this paper, and Fourier decomposition was performed on the air gap magnetic density and the analytical formula of cogging torque under unequal tooth width was derived. The influence rule of unequal tooth width on cogging torque and the variation rule of weakening effect with deflection angle of stator tooth slot were obtained. The optimal deflection angle which can effectively suppress the cogging torque was given. The results were verified by finite element method. Secondly, the output torque of the motor with holes in the rotor yoke was studied and the influence rule of the hole shape, size and number on output torque was analyzed. The simulation analysis shows that the output torque can be appropriately increased by opening holes in the rotor yoke, and the optimum hole shape, size and number are achieved.