PQ变换与大型感应电机转子故障诊断

PQ transformation and rotor fault diagnosis for large induction motors

为避免频率检测误差对感应电机转子故障诊断的影响,提出了一种基于PQ变换的转子断条故障诊断新方法.利用电机的端电压,构造PQ变换矩阵,将电机端电流变换到PQ平面,实现了转子断条故障特征的可靠抽取,从而不受电网供电频率波动的影响.该方法不仅克服了电流频谱分析方法的不足,而且解决了Park矢量分析法时图形识别难的问题.定义了一种新的独立于负载等级及惯量大小的故障严重因子,给出了可靠区分转子故障与负荷波动的方法,实验结果证明了该方法的有效性.

A new rotor fault diagnosis method for induction motors based on the double PQ （active power P and reactive power Q） transformation was presented in order to avoid the influence of frequency error. The PQ transformation matrix was constructed by the terminal voltages of induction motor, and the terminal currents were transformed to PQ plane, accordingly the rotor broken bar faults were taken out reliably, and the influence of supply frequency fluctuation could be avoided. The proposed method overcomes the methodological shortages based on analysis of the stator current spectrum, and solves the difficult of Park vector method to recognize graphics. A new fault severity index independent of load level and mechanical inertia was given, and then a method to reliably discriminate between rotor faults and load fluctuation was presented. Experimental results demonstrated the validity of the proposed method.