Boostbuck or Cuk Switching Converter

[D from BC]

Thanks for the info Kensmith.

I'm new at posting..A reply went out before I completed writing.

Neglecting the controller propagation delay and transient times
for the moment..

It's those poles and zeros in the Cuk top. I'm wondering about..

I've made bode plots of amplifiers.. Set an operating point and
sweep a sine...easy..
Look at the gain and phase and one can determine stability.

But the Cuk...it's like 2 operating points (on&off) switching a
RLC network with a duty and frequency. With a hysteresis
controller the timing is formed by the output inductor current
banging into the hysteresis limits. (Hysteresis control current
feedback.)

I've heard that Cuk Topology (and like switchers) can be
tranformed so that spice can make a bode plot. Something to do
with replacing the catch diode and switching Mos with functions
so that the switching is averaged..
I'm not sure but I think the whole network is warped into some
linear approximation so that there's one operating point and a
sweep can be done. (I've noticed some spice programs are using
blocks for buck and boost..)
....And this is where I lose it...How to sweep a Cuk?

While writing this I did notice the post about LTSPice and
averaging ..so I'll check that out. Thanks