永磁同步电机低转矩脉动的稳健设计

在电机生产加工过程中引起的尺寸和形位公差、安装误差、材料属性偏差等噪声因子,造成了批量生产的电机间的转矩脉动特性分散,进而影响高精度永磁同步电机系统控制性能的一致性。为保证高精度场合用永磁同步电机的转矩脉动特性具有良好的稳健性,采用田口稳健设计方法,选取的噪声因子包括磁钢的周向安装位置、充磁角度、剩磁大小的误差、气隙加工误差、转子静态和动态偏心以及传感器安装误差等,通过优化磁钢、齿槽、气隙等电磁设计参数的名义尺寸,达到降低转矩脉动系数的均值和分散区间的目的。对比分析了稳健设计、正弦反电势设计和均匀气隙设计3种方案,结果表明,在相同噪声因子的影响下,与另两种设计方案相比,采用稳健设计方案,转矩脉动系数的均值和均方差显著降低。以转矩脉动系数作为优化目标,有效地满足了转矩脉动和平均转矩的多目标优化要求。

Robust Design for Reducing Torque Ripple in Permanent Magnet Synchronous Motor

The production process of the motors causes dimension tolerances,shape and position tolerances,installation errors,deviations of material properties.These noise factors lead to the distribution of torque ripple characteristics among the lot-production of motors.Furthermore,it affects the consistency of control performance in the high-precision permanent magnet synchronous motor system.To ensure a good robustness for the torque ripple characteristics of the permanent magnet synchronous motor used in high precision servo system,Taguchi’s robust design method was employed.The noise factors included the installation position deviations of the magnets along the circumferential direction,the magnetization angle,the remanence of the magnets,the rotor static and dynamic eccentric,the air-gap length and the installation of position sensors.The average value and distribution range of the torque ripple factor were reduced by optimizing the nominal sizes of magnets,slot,air gap and other electromagnetic design parameters.The robust design scheme was compared with the other two schemes with the sinusoidal back EMF waveforms and with uniform air gap.The results demonstrated that the average value and the mean square deviation of the torque ripple factor were reduced obviously in the robust design compared to the other two designs.It well meets the multi-objective optimization requirements of ripple torque and average torque by taking the torque ripple factor as optimal objective.