how to use PLECS and SIMULINK Analysis tools to get the frequency response?

hello everyone,
I want to get the frequency response of my boost DC-DC converter with peak current mode control. I have tried to use the Plecs AC sweep and Analysis tools of Simulink.
when I use these tools in open loop I get a really nice bode plot of my converter.However, when I use it in the closed loop (peak current mode control) I am getting completely a meaningless bode plot a took me one day to get it.
AS I am targeting the Vout/Verr transfer function of my boost converter with peak current mode control. I want to know whether I should add the output of AC sweep before the PID controller and the input of the AC sweep is the Vout(which I actually did but got wrong bode plot) or there are othere things I am missing!!.
I did it also with Linear Analysis tools of Simulink and I got the same meaningless bode plot.
what I don#t understand is as long as my model is working why I am getting wrong bode plot?
Cheers,

You should clarify your simulation setup with a schematic. You can also post zipped Plecs or Simulink simulation projects, may be someone who's working with one or the other tool is motivated to take a look.

thanks, i am going to upload my circuit