If I have an isolated Cuk topology with dual primaries where both input voltages are floating, and I'd like to drive the single secondary from only one primary supply at a time, with the other shut down not sinking or sourcing any current.
I have a question about the series inductors on the primary and secondary side which in the single primary, single secondary case are often transformer-coupled to reduce output ripple. Is there a way to time the switches S1, S2, S3 (assume I can synchronize them in an isolated way via an optocoupler or something), and/or arrange the secondary-side inductors L3, L4 in series/parallel such that they can be coupled to their respective inductors on the two primaries, but only act at any given time as would be expected in a Cuk with a single primary winding, and don't back-feed the source on the other primary which is supposed to be shut down.
Or do something else clever that hopefully doesn't require custom magnetics. Or just don't couple them and have a single inductor on the secondary that's a compromise value and deal with it.