Method for the electronic diagnosis of an electric drivetrain for a motor vehicle

A method for electronically diagnosing an electric drive chain for an electric or hybrid motor vehicle, the drive chain comprising an electric battery, an electric machine, an inverter connected between the battery and the electric machine, and a link capacitor connected in parallel between the battery and the inverter, the diagnosis method comprising:

• i) continuously controlling the increase in the control frequency of the electric machine from a minimum value to a maximum value;
• ii) continuously measuring the value of the current between the assembly comprising the battery and the link capacitor and between the inverter (20) during the control step;
• iii) determining the variation in the Fourier transform of the received current variation as a function of the control frequency;
• and
• iv) for each control frequency:
• 1) detecting an anomaly if at least one value of the Fourier transform is outside a predefined Fourier transform interval for said control frequency;
• 2) otherwise, determining when said control frequency value is optimal if the value of the Fourier transform for said control frequency is below a predefined threshold.