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 including 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 includes: i) continuously controlling the increase in the control frequency of the electric machine; ii) determining the variation in the Fourier transform of the current variation between the assembly comprising the battery and the link capacitor and between the inverter; iii) for each control frequency: 1) detecting an anomaly; 2) otherwise, determining when the control frequency value is optimal.