Unexpected noise in output voltage for buck converter

Hello! I'm trying to simulate the buck converter using statespace equations. I don't understand why the output voltage has a ripple in the second photo (uncompensated system) and then, in the first one there is no ripple (compensated system)

[madhan ravi]

See the y axis scale of each picture.

Why not directly use simscape electrical https://www.mathworks.com/help/physmod/sps/ug/buck-converter-voltage-control.html?s_tid=answers_rc2-3_p6_MLT ?

[Vasilica Cioban]

no, this isnt the problem. i tried to zoom in the both of them and the first one is just a line without any ripple

Answer 1

[Pat Gipper]

The Puse Generator has a period of 1/100000 seconds, which is injecting 100 KHz pulses into your system. The ripple is simply the response to those pulse. Try setting Period=10 and Amplitude=24 and you will get rid of the ripple.