i can add this much, the primary windings of the alternator is smaller than the secondary windings, all it is - is a spinning transformer. even though the primary windings are smaller, the output is still stepped up. this is only true because the alternator spins and "the way the rotor magnifies the secondary".
But you have replicated the rotor spinning as i said, so now you get the same output "not using a driver motor to spin the alternator," but using electronics to pulse the transformers instead.
if you use the proper transformer i would not see why it would not be possible to drive the transformers input using the transformers output, "the alternator does it." even if you fail to replicate the "perpetual like ideal" you can still send 3 phase harmonics to the circuit using a battery like you have been showing in your circuits.
it should be understood that when you drive 1 transformer you can not pulse it with 1 square wave, as i have said before under a oscilloscope using a pwm to pulse only 1 side of a transformer will output a capacitor discharge wave to the cell and not a sine discharge wave.
just so you are not lost, and i cant explain this sorry, but the alternator some way under the oscilloscope is square waves and not sine waves, me and stevie confirmed this. the top of the square waves has 3 phase harmonics. its unbelievable.