Not that it's a good topology or something, it's actually very bad and inefficient, but it's just a sort of prototype thingy. The only advantage I see is the negative feedback, which keeps the output at stable ~320V, at any load level up to about 130W. This is actually very sought-after in invertors, but can rarely be achieved without some hardcore feedbacks and complex circuitry. Other than that the efficiency is veery bad at 25%, but I'm bored and can't go to sleep yet, so deal with it :D just kidding.
