Frequency demodulation-aided condition monitoring for drivetrain gearboxes

Abstract

Abstract-Condition monitoring and fault diagnosis (CMFD) of drivetrain gearboxes has become a prominent challenge in assorted industries. Current-based diagnostic techniques have significant advantages over traditional vibration-based techniques in terms of accessibility, cost, implementation and reliability. This paper proposes a current-based, frequency demodulation-aided CMFD method for drivetrain gearboxes. A mathematical model is developed for a drivetrain consisting of a two-stage gearbox and a permanent magnet synchronous generator (PMSG), from which the characteristic frequencies of gearbox faults in the PMSG stator current are derived. An adaptive signal resampling method is proposed to convert the variable fault characteristic frequencies to constant values for the drivetrain running at variable speed conditions. A demodulation method, combining the Hilbert transform, a finite impulse response (FIR) differentiator, and a phase unwrapping algorithm, is developed to extract the instantaneous frequency (IF) patterns that are related to the faultinduced gearbox vibration. A fault detector is proposed for diagnosis of gearbox faults using statistical analysis on the extracted fault signatures. Experimental studies are carried out to validate the effectiveness of the proposed method.

A Survey on Wind Turbine Condition Monitoring and Fault Diagnosis—Part I: Components and Subsystems

“…A fault may induce new characteristic frequencies in the signals or may only change the amplitudes of the existing characteristic frequency components [20]- [23]. The latter cannot be detected by solely using frequency analysis methods and will require additional statistical analysis for the characteristic frequency components [20], [21].…”

A GA-SVM hybrid classifier for multiclass fault identification of drivetrain gearboxes

“…If the drivetrain gearbox is connected to an AC electric machine, the characteristic frequencies of the gearbox vibration will modulate the stator currents of the AC machine and generate sidebands across the dominant components in the frequency spectra of the currents [8]. As demonstrated in [5], [8], [9], the faults in a gearbox that change the characteristic frequencies of the gearbox vibration will subsequently change the sideband distribution in the frequency spectra of the current signals of the AC machine. For a drivetrain consisting of a multistage gearbox connected with a PMSM, the characteristic frequencies of the faults in a gearbox vibration signal include the shaft rotation-related frequencies ( 1, 2, … , , is the number of gears in the gearbox), and gear meshing-related frequencies…”

Fault diagnosis for drivetrain gearboxes using PSO-optimized multiclass SVM classifier

“…Prior work has demonstrated the effectiveness of currentbased methods for CMFD of gearboxes [5]- [7]. However, the previous work assumed that the gearbox had been in faulty condition but did not address the diagnostic task when the condition of the gearbox is unknown.…”