基于瞬时频率分析的笼型电机转子断条故障诊断

摘要

The motor current signature analysis (MCSA) method for diagnosing broken rotor bars faults in squirrel-cage motor had some drawbacks that the diagnostic effects were subject to running state of the motor,which could even lead to a wrong diagnosis of the fault.A novelty approach based on the instantaneous frequency analysis of the start-up transient was presented.The proposed approach consists of extracting the mono-component signals from the start-up current by FIR low-pass filtering technique and calculating the instantaneous frequency of the obtained signal,via the derivative of the phase of the analytical signal,and according to the characteristic pattern of the IF-s on the f-s plane,it was judged if the broken rotor bar defect occurs.The experiment verification was performed on a 3 kW motor test bench;the experiment results proved the effectiveness of the proposed method.%电机电流信号特征分析方法诊断笼型电机转子断条故障时,诊断效果受制于电机运行状态的影响,甚至会发生误诊断.针对这一问题,提出基于瞬时频率分析的笼型电机转子断条故障诊断方法.首先对起动电流进行FIR低通滤波,以提取包含转子断条故障特征的单分量谐波信号,然后采用相位微分方法计算该信号的瞬时频率,并根据f-s平面上的瞬时频率-滑差曲线判断故障发生与否.在3 kW电机试验平台上对所提出的方法进行验证,试验结果表明了所提方法的有效性.