基于VMD与不同包络阶次构造的风电机组滚动轴承故障诊断

针对风电机组变工况滚动轴承故障诊断问题，将变分模态分解（variational mode decomposition，VMD）与计算阶比跟踪（computed order tracking，COT）、逆包络阶次谱（reversed sequence squared envelope spectrum，RE-SES）2种方法结合进行包络阶次分析；将非平稳的时间域信号转换成平稳的角度域信号，再经包络法找出滚动轴承故障特征信息。仿真与实验结果表明，VMD结合RE-SES包络阶次法可以更加有效地提取出调幅信号中的调制阶次，并且VMD滤波可以使得故障特征阶次更加凸显，易于故障识别，为风电机组变速工况下的滚动轴承故障诊断提供参考。

Fault Diagnosis of Rolling Bearing of Wind Turbine Based on VMD and Different Envelope Order Structure

In order to identify the faults of rolling bearing of wind turbines, the variational modal decomposition (VMD) was combined with two methods, including calculation order tracking (COT) and reversed sequence squared envelope spectrum (RE-SES), to carry out the envelope order analysis. The non-stationary signals in time domain were converted into stationary signals in angle domain by equal angle sampling. And the bearing fault characteristic information was obtained by envelope method. The results show that the modulation order of amplitude modulation signal can be extracted more effectively by VMD combined with RE-SES envelope order method. The VMD filter could make the fault feature order more prominent, and it is easy to identify the fault, and it provide reference for the fault diagnosis of rolling bearing of wind turbine under variable speed condition.