基于半周反电势残差的永磁同步电机局部退磁故障诊断

Local demagnetization fault diagnosis of permanent magnet synchronous motor based on half-period back EMF residual

永磁体退磁故障的精准定量诊断,对于预防电机发生灾难性故障和系统运行维护策略的制定至关重要。为实现退磁永磁体定位及程度评估,本文提出了一种基于半周反电动势残差的局部退磁故障诊断方法。在定子槽内安装一个探测线圈,提取其反电动势残差信号并进行分区;将分区后的反电动势残差峰值作为特征量进行退磁故障类型识别,进而确定相邻两个永磁体的健康状态及退磁程度,利用一个旋转周期的信号确定所有永磁体的状态,具有侵入性小、计算量小和精确度高的特点。首先,介绍了探测线圈的安装及检测机理,建立了永磁同步电机退磁故障下的探测线圈半周反电动势残差数学模型;然后,提出了考虑支路环流的反电动势残差提取算法,有效提高了探测线圈反电动势残差提取的精确度;最后,建立了反电动势残差峰值与退磁永磁体位置及退磁程度的映射关系,并提出了退磁永磁体定位及程度评估算法,实现了永磁同步电机局部退磁故障的精准定量诊断。仿真和实验结果验证了所提方法的正确性和准确性。

Accurate quantitative diagnosis of permanent magnet demagnetization fault is essential for pre-vention of catastrophic motor fault and formulation of system operation and maintenance strategies.In or-der to realize the demagnetization permanent magnet location and degree evaluation,a local demagnetiza-tion fault diagnosis method was proposed based on half-period back electromotive force(EMF)residual.In the method,a search coil was installed in the stator slot to extract its EMF residual signal and partition it;the partitioned EMF residual peak value was used as a characteristic quantity for demagnetization fault type identification,which in turn determines the healthy conditions of two adjacent permanent magnets and the demagnetization degree,using the signal of one rotation period to determine the status of all per-manent magnets.The proposed method is less invasive,less computationally intensive and highly accu-rate.The installation and detection mechanism of search coil was introduced,and the mathematical mod-el of search coil half-period back EMF residual was established under demagnetization fault of permanent magnet synchronous motor(PMSM).Then,an algorithm was proposed to extract the EMF residual con-sidering the branch circulating current,which effectively improves accuracy of the search coil EMF resid-ual extraction.Finally,the mapping relationship between the EMF residual peak value and the location and demagnetization degree of demagnetization permanent magnet was established,and an algorithm for location and degree evaluation of demagnetization permanent magnet was proposed to achieve accurate quantitative diagnosis of local demagnetization fault in PMSM.Simulation and experimental results verify correctness and accuracy of the proposed method.