风电齿轮箱振动信号耦合调制建模与应用

Modeling and application of coupled modulation of vibration signals in wind power gearboxes

风电齿轮箱不同轮系间存在的耦合调制现象干扰了实际故障诊断,为此,针对两级行星一级平行结构的齿轮箱提出一种考虑级间耦合调制的现象学模型。首先,在风电齿轮箱振动信号幅值、频率解调分析基础上,定义了多级传动下的级间串联调制特性,并提出幅值-频率级间串联调制模型;通过构造多级调幅信号和调频信号,在频谱和解调谱中对串联调制特性进行仿真分析,并提出耦合调制特性边带能量指标用于模型评价;设计了与现场齿轮箱具有相同结构的缩比齿轮箱实验台,并在正常与故障状态下进行实验、现场联合分析,验证级间串联调制模型的有效性。结果表明:频率耦合调制现象在四种状态下尤为明显,其耦合调制特性边带能量分别为1.02、1.04、1.18、1.25。本模型所反映的齿轮箱级间耦合调制现象是齿轮箱本身所有,不会因齿轮箱的状态而发生改变,本模型为提高风电齿轮箱故障诊断准确性提供参考。

The coupling modulation phenomenon between different gear trains of wind turbine gearbox interferes with the actual fault diagnosis.Therefore,a phenomenological model considering interstage coupling modulation is proposed for a two-stage planetary one-stage parallel gearbox.Firstly,based on the amplitude and frequency demodulation analysis of vibration signal of wind power gearbox,the characteristics of series modulation between stages under multistage transmission are defined,and the series modulation model between amplitude-frequency stages is proposed.By constructing multistage amplitude-modulation signal and frequency-modulation signal,the series modulation characteristics are simulated in both the spectrum and demodulation spectrum,and the sideband energy index of coupling modulation characteristics is proposed for model evaluation.A scaled gearbox test bench with the same structure as the field gearbox is designed,and experiments and field analysis are carried out under both normal and fault conditions to verify the validity of the series modulation model between stages.The results show that the frequency coupling modulation phenomenon is particularly obvious in the four states,and the sideband energies of the coupling modulation characteristics are 1.02,1.04,1.18 and 1.25,respectively.The coupling modulation between gearbox stages reflected in this model is the gearbox itself,and will not change with the gearbox state.This model provides a reference for improving the fault diagnosis accuracy of wind power gearbox.