基于d-q理论的双馈异步电机定子匝间短路故障诊断方法

Diagnosis method of stator inter-turn short-circuit fault in double-fed asynchronous motor based on d-q theory

为实现双馈异步电机定子绕组匝间短路的早期故障诊断,提出一种基于转子电流特征频率分量的故障诊断方法 .首先,通过分析故障后电机的电磁特性,得到故障后转子电流中会产生特征频率分量的结论 .然后,通过对转子单相电流进行特殊的相移构造出三相电流,并对该组电流进行d-q变换,利用理论推导证明d-q变换后的直流分量幅值能够反映特征谐波的大小,将直流分量作为故障特征量进行双馈异步电机匝间短路故障的诊断.最后,依据有限元法建立故障前后电机的仿真模型,对不同工况下故障特征量的变化进行研究.结果表明:基于d-q理论提取的故障特征量与定子绕组的短路匝数呈正相关,且在转速变化和电压不平衡时也可有效诊断出匝间短路故障;通过设置合理的故障阈值可实现对双馈异步电机定子绕组匝间短路故障的精确辨识.研究结果可以为电机绕组匝间短路故障诊断提供参考.

This paper proposes a fault diagnosis method based on the characteristic frequency compo-nent of rotor current for early detection of inter-turn short-circuit faults in the stator windings of double-fed asynchronous motors.Firstly,the electromagnetic characteristics of the motor post-fault analysis indicate the generation of a characteristic frequency component in the rotor current.Then,a three-phase current is derived from a specific phase-shifted single-phase rotor current,followed by d-q transformation to demonstrate that the amplitude of the transformed DC component reflects the mag-nitude of the characteristic harmonics.This DC component serves as a fault characteristic quantity for diagnosing inter-turn short-circuit faults in double-fed asynchronous motor stator windings.The fault diagnosis for turn-to-turn faults is conducted using finite element theory.Finally,a simulation model of the motor pre and post-fault is established utilizing the finite element method to investigate the varia-tions in fault characteristic quantity under diverse operational conditions.The results indicate a positive correlation between the fault characteristic quantity extracted using the d-q theory and the number of short-circuited turns in the stator winding.Effective diagnosis of inter-turn short-circuit faults is achieved under variable rotational speeds and unbalanced voltages through the setting of reasonable fault thresholds,providing a new methodology for diagnosing turn-to-turn short-circuit faults in motor windings.