针对异步电动机故障特征难以提取的问题,引入基于功率频谱的故障诊断方法.三相平均功率频谱将定子电流中的基波变换为功率频谱中的直流分量,从而达到突出故障特征、准确分离复合故障的效果,但必须考虑电源和负载的对称度.单相功率频谱无法诊断定子绕组故障,却对诊断转子断条故障非常有效.理论推导与仿真表明,功率频谱具有故障特征明显、信息丰富、诊断灵敏度高、对采样分辨率要求低的优点,可用于异步电动机的故障诊断.%To solve the problem in obtaining fault characteristics of asynchronous motor, a fault diagnosis method based on power spectrum is proposed. Three-phrase average power spectrum transforms the fundamental stator current into DC component of power spectrum. It achieves to distinguish fault characteristics and separate combined faults accurately. However, the symmetry degree of power and load must be taken into consideration. Single-phrase power spectrum is unable to diagnosis stator wingding fault and is able to diagnosis broken rotor bar fault effectively. Theory derivation and simulation results show that power spectrum is preponderant with obvious fault characteristics, abundant fault information, high diagnosis-sensitivity and low sample resolving-power requirement. Therefore, power spectrum is feasible to be applied in motor fault diagnosis.
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