inverter 12vdc-220vac sin

i don't study electric,i like it and i make it
i download a circuit,i don't calculated a T3,T4 and some function of circuit
can u help with me?

T3 and T4 are balanced inductors that are part of the output filters. They must not saturate when the max output current of the inverter passes through them and their value depends on the switching frequency.