Frequency adaptive FRFT filtering-based air gap eccentricity fault detection method for variable frequency induction motor

The invention relates to the technical field of motor fault diagnosis, in particular to a variable frequency induction motor air gap eccentricity fault detection method based on frequency adaptive FRFT filtering. The method comprises the following steps: S1, collecting a phase stator current instantaneous signal; s2, calculating short-time Fourier transform of each segment of current signal, and constructing a time-frequency matrix; s3, constructing a time-varying curve of the fundamental wave frequency; s4, performing piecewise linear fitting on the fundamental wave instantaneous frequency curve, and adaptively segmenting the current signal into multiple sections of linear frequency modulation signals; s5, fractional order Fourier transform is carried out on the linear frequency modulation signals, and fundamental components are filtered out; and S6, generating a time-frequency diagram, and judging whether the motor has an air gap eccentricity fault or not. According to the variable frequency induction motor