dear Aristide Foudji,

You must chose a appropriate number of cycles to be sure that Matlab/simulink performance correct FFT analyse. you can choose 20 cycle of the waveform.  I guess that your problem can be solved.

if  you agree with my answer, please approve this.

thanks

Aristide,

Can you post a zoomed single cycle of the waveform ? This one is too cramped up to interpret anything !

-SAnjay

I have tried to get the better resolution, but i can't . I mean when i upload the image, the web site compress it.The figure/images provide is from Scope using while simulate PMSG wind power type using simuling model. I'm sorry for the image quality but i can't provide the better one.

dear Aristide Foudji,

You must chose a appropriate number of cycles to be sure that Matlab/simulink performance correct FFT analyse. you can choose 20 cycle of the waveform.  I guess that your problem can be solved.

if  you agree with my answer, please approve this.

thanks