Research On Automatic Fault Identification Of Wind Turbine Gearbox Based On Amplitude Modulation Ratio

The total installed capacity of wind turbines increase greatly, resulting in the higher demand for reliability of the operation of wind turbines, therefore the automatic fault diagnosis of wind turbines play great roles in the further development of wind energy. In this article, select the wind turbine gearbox for research, and then one automatic fault diagnosis algorithm based on amplitude modulation has been proposed.In this discussion, great attention focus on the introduction related to gearbox vibration mechanism, vibration signal model, fault type and cause of gear,fault type and fault characteristic frequency of rolling bearing, resulting one amplitude modulation algorithm based on algorithm named sideband energy ratio has been proposed. Apply this method in the procession for constant speed data and select the amplitude modulation ratio as a feature value for reflection of gear fault. The experimental results show the validity of the proposed amplitude modulation algorithm in the constant speed gear fault diagnosis, reflecting the degree of modulation related to the gear clearly. Meanwhile, the algorithm named order analysis has been introduced in for the fault diagnosis of gear due to the proposed algorithm is not applicable for the process of vibration signal under variable speed. In addition to this, the time frequency analysis technique has been introduced into order domain, applying the relationship between the instantaneous frequency obtained by time frequency analysis and the rotating shaft of mechanical equipment into order analysis of vibration signal. Eventually, the experiment results show effectiveness of order analysis in the process of gearbox data,through the use of order analysis to deal with the corresponding data.The effectiveness of amplitude modulation in gear fault diagnosis and the combination with order analysis for gear vibration data under variable speed have been proved.The instantaneous frequency estimation introduced into this article can ac quire the instantaneous frequency associated with rotator speed in the mechanical equipment directly from the gear vibration signal and get full speed curve through corresponding curve fitting. Finally, the key phase is obtained via the curve fitting polynomial coefficients. And then, achieve order tracking through the key phase. All in all,this method can solve the problems of the traditional order analysis, such as use of rotating speed meter, the key phase device, to reduce the cost of order analysis.In this article, cope the corresponding data with envelope processing directly,and then deal the corresponding data with order envelope spectrum processing in bearing fault diagnosis, using the rotating frequency obtained from time-frequency analysis extraction. The effectiveness of time-frequency order analysis for the fault diagnosis of rolling bearing has been proved, through the comparison the result of the actual bearing data processing.