永磁伺服电机嵌入式位置检测理论及误差分析

Embedded position detection theory and error analysis for permanent magnet servo motors

针对现有的永磁伺服电机位置传感器存在成本高、体积大的缺点和新兴的无传感器技术计算复杂及依赖电机参数的不可靠性问题,提出了绕制时栅线圈检测电机转动位置的方法,但由于绕制时栅线圈检测的方法存在获取信号复杂、测量稳定性差以及线圈绕制不均匀增加误差的缺点,在此基础上,提出了一种基于隧道磁阻效应(TMR)和时栅技术的永磁伺服电机嵌入式位置检测新方法。在原理分析的基础上,根据行波表达式的理论推导,分析了单路和双路驻波幅值不相等所导致的误差规律,为检测结构的优化和进一步提高测量精度奠定基础。最后通过实验,验证了嵌入式位置检测理论分析的正确性以及检测方案的优越性,所提出方法的检测精度较绕制时栅线圈的检测方法提高了3倍,稳定性提高了5倍。

Aiming at the deficiency of high cost and large volume existing in the position sensor of permanent magnet servo motor,as well as the disadvantage of the computation complexity and the unreliability due to relying on the motor parameters existing in the newly developed sensorless technology,the time grating displacement sensor research group proposed a method for detecting the motor rotation position through winding time grating coil. However,because the detection method through winding time grating coil has the shortcomings of complex signal acquisition,poor measurement stability and increasing error due to the uneven coil winding. On the basis of above,this paper proposes a new embedded shaft position detection method for permanent magnet servo motor based on tunnel magnetoresistance（TMR） effect and time grating technology. The position detection principle is analyzed in detail. According to the theoretical deduction for travelling wave expression,the measurement error characteristics caused by the unequal amplitudes of one and two channel standing waves are analyzed,which lays a foundation for the detection structure optimization and further improving the measurement accuracy. At last,the experiment verifies the correctness of the embedded position detection theoretical analysis and the superiority of the proposed detection method. Compared with the detection method through winding time grating coil, the proposed method improves the measurement accuracy nearly by three times and improves the stability by five times.