FFT Analysis using powergui (SimPowerSystem)
How to use SimPowerSystems FFT:

First make a model and Export to Desktop the waveform you would like to use the function over:



Here you see a simple 3 phase rectifier &amp; the 3phase measuring block.  The line currents are being exported to the workspace (as a structure + time) 

Run the simulation to populate the workspace with the results.

Under powergui choose FFT Analysis



What you will find is it would have loaded in any structure+time data it can find. Set the fundamental, set the number of cycles you wish (more you have, the higher the harmonic content you can analysis)

Then choose between bar or list.



My advise however is learn how todo FFT in matlab (and then thd etc...). Its alot more versatile and you can then script it. I think this is probably the 3rd time I have used the FFT Analyser and I use SimPowerSystems daily