raypsi wrote:

snip
I agree it's not a flyback.

I don't think it's resonant converter because you looky at VK3HZ's
data on loading it, the duty cycle would take it way out of resonant.


I'm sorry, I should have been more precise in my use of terms.

It's zero voltage switching or ZVS which is resonant transition.
The resonance is much higher than the swicthing frequency and it
isn't effected by the changes in duty cycle. Although it does
steal some on-time

Sometimes it's called quasi-resonant and there's a variant called
ZCS or zero current switching.

It's not a resonant converter like series or parallel resonant
converters where the output is controlled by shifting the frequency.