基于低分辨率位置传感器的永磁同步电动机转矩脉动控制

Torque ripple control of permanent magnet stepper motor based on low resolution position sensor

电动助力转向系统由于其良好的燃油效率和转向性能,被广泛用于汽车中,但存在材料成本高和转矩脉动大的问题.采用低分辨率位置传感器能够降低电动助力转向系统材料成本,但编码器信号引起的电流谐波会增加转矩脉动.基于此,分析了转矩脉动的影响因素,采用测量编码器信号频率估算转子位置和转速,获得q轴补偿电流并施加到电流指令中,从而使6阶转矩谐波逐渐衰减.实验结果表明:通过应用估算的转子位置和转矩脉动补偿,转矩脉动波峰的峰值占平均转矩的百分比从6.25%降至1.60%,证明了所提出的控制方法有效地减小了转矩脉动,降低材料成本.

Electric power steering system is widely used in automobile because of its good fuel efficiency and steering performance,but it has high material cost and high torque ripple.The low resolution position sensor can reduce the material cost of the electric power steering system,but the current harmonic caused by the encoder signal will increase the torque ripple.Based on this,the influence factors of torque ripple are analyzed.The position and speed of the rotor are estimated by measuring the frequency of the encoder signal,and the compensation current of the q axis is obtained and added to the current instruction,so that the 6 order torque harmonics are gradually attenuated.The experimental results show that by using the estimated rotor position and torque ripple,the percentage of the peak of the torque ripple to the average torque is reduced from 6.25%to 1.60%.It is proved that the control method proposed in this paper reduces the torque ripple and the effectiveness of reducing the material cost.