What you call SPWM can only be applied only in two ways to enact an inverter, 1) to a set of 4 fets running off a 350V bus, to provide the desired Vac out, needs to be filtered to remove the sw freq, and,
2) on a low volt set of fets intended to drive a transformer to get 230Vac (for eg) at 50/60Hz, filtering still needed somewhere, either LV side or HV side.
If the latter then the Tx needs to rated as for a normal mains Tx + the sw losses it will incur.
For 1) above some where a step up stage has been used to create the 350VDC
For 2) the mains Tx does the step up, many commercial inverters and grid tied inverters use a mains Tx this way.