用于精密加工的三相磁通切换永磁直线电机的研究与分析

Study and Analysis of a 3-Phase Flux-switching Permanent Magnet Linear Motor for Precision Machining

数控机床常用的驱动方式为旋转电动机+齿轮或皮带等中间传动装置,但是这种方式存在有很多的缺点,如摩擦、反向间隙等都会直接影响并限制数控机床的加工精度。该文提出一种用于精密加工的三相磁通切换永磁直线电机,该种直线电机继承了永磁磁通切换电机和直线电机的优点,由于它可以采用直接驱动的方式而不需要中间传动环节,因此可以显著提高数控机床的加工精度。首先,文章给出了该电机的基本结构并分析了其工作原理;其次,基于有限元法对电机进行仿真和分析,并研究其特性,如磁场分布、空载反电动势、绕组磁链、绕组电感和电磁推力等,通过对仿真结果分析发现绕组磁链和反电动势的波形本质上均为正弦波;最后,对不同永磁体厚度、气隙、电流和速度下的电磁推力进行比较和分析以研究推力随这些参数的变化情况。

The general driving system for computer numerical control （CNC） machine tools usually consists of rotary motors and intermediate gearings such as belts and gears, however, this kind of system has the disadvantages of friction and backlash which can directly influence and limit the machining precision of CNC machine tools. In this paper, proposed and analyzed a 3-phase flux-switching permanent magnet linear motor （FSPMLM） for precision machining. The proposed linear motor inherits the advantage of both flux-switching permanent magnet （FSPM） machine and linear machine and can significantly increase the machining preci- sion of CNC machine tools because of applying a direct driving method without intermediate gearings. Firstly, the topology and principle of operation were given out. Secondly, finite element method （FEM） was employed to investigate the proposed FSPMLM and analyze its characteristics, such as magnetic field distribution, no-load back-EMF, flux-linkage, inductance and thrust force. It is found that both the flux-linkage and back-EMF are essentially sinusoidal. Lastly, the thrust force under different thickness of PM, air-gap, current and velocity was compared and analyzed to find how the thrust force varies with those parameters.