永磁直线伺服电机的磁场分析及优化设计

Magnetic analysis and optimization of permanent magnet linear servo motor

介绍了一种圆筒型永磁直线伺服电机,电机次级采用轴向磁通结构,初级采用无铁心空心式绕组设计,完全消除了传统有铁心永磁电机固有齿槽效应所引起的推力波动问题.该结构电机的输出推力稳定性主要与电机气隙磁场分布的正弦程度有关,提高气隙磁场分布的正弦性是改善电机伺服性能的重点.通过对电机磁场进行有限元分析,研究了电机次级永磁体宽度和半径2个主要尺寸对气隙磁场分布的影响,并给出了这2个主要尺寸的最佳取值.经过优化设计,电机的气隙磁场分布得到了改善,磁场谐波分量大大降低,输出推力更加稳定,伺服性能得以提高.

A novel tubular permanent magnet linear servo motor was proposed. The motor applies the axial magnet array topology of the secondary rod, and the air-cored armature windings and slotless structure of the forcer, which totally eliminates the cogging force of general permanent motors. The stability of thrust is mainly related to the sinusoidal degree of magnetic field distribution, so the way to improve the sinusoidal distribution of magnetic field is the major work to improve the motor performance. Based on magnetic finite element analysis, the influences of two major dimensions, the pitch and radius of permanent magnet, to the magnetic field were studied and the best values were given. The magnetic field distribution was greatly improved after the secondary rod optimization with much lower harmonic component of the magnetic field, more stable thrust, and improved motor＇s servo performance.