异步电机定子匝间短路故障检测系统设计

Design of stator inter-turn short-circuit fault detection system for asynchronous motor

为了实现对异步电机定子早期匝间短路故障的在线检测,文中设计一种定子匝间短路故障检测系统。根据定子电流中匝间短路的故障特征频率方程确定系统滤波的频率范围;利用电流互感器获取电机电流信号,并经硬件电路完成放大和滤波处理;利用经验模态分解对故障特征频率进行初步提取,并提出新的方法抑制密集模态混叠现象;结合Hilbert包络解调,实现故障特征频率的提取并减轻频谱泄漏影响;最后经频谱分析提取故障特征频率,检测电机是否存在定子匝间短路故障。对不同故障程度的电机进行检测,对所设计方法抑制密集模态混叠现象的性能进行对比,得出检测结果准确,抑制效果能满足要求。多次实验结果表明,所设计系统的实时性好,能够实现对异步电机早期轻微匝间短路故障的在线检测,并预防严重故障的产生,具有一定的实用价值。

In order to realize the on-line detection of early stator inter-turn short circuit fault of asynchronous motor,a detection system for stator inter-turn short circuit fault is designed. The frequency range of system filtering is determined according to the fault characteristic frequency equation of inter-turn short circuit in stator current. The motor current signal is obtained by means of current transformer,and then is amplified and conducted the filtering process by means of hardware circuit. The fault characteristic frequency is extracted preliminarily by means of the empirical mode decomposition. A new method is proposed to suppress dense mode mixing. In combination with Hilbert envelope demodulation,the extraction of fault characteristic frequency is realized,and the influence of spectrum leakage is reduced. The fault characteristic frequency is extracted by means of spectrum analysis to detect whether there is stator inter-turn short circuit fault in the motor. The motor with different levels of faults is detected. By comparing the designed method ’ s performances to suppress dense mode aliasing phenomena,it is concluded that the detection results are accurate and the suppression effect can meet the requirements. The designed system has good real-time performance,can realize online detection of early slight inter-turn short circuit fault of asynchronous motor,and prevent serious fault occurrence,so it has a certain practical value.