Quote Originally Posted by dknagare
Hi,

I have already tried transformerless( only small ferrite core of EE65X13) design upto 1000W but output was squarewave. Now I will use SPWM signal to convert DC to AC. In this type it easily possible to make 3Phase output without much circuit.

My main aim is to make sinewave inverter without using bulky iron core. I will upload some details very soon.
Thanks a lot for information. For long time nobody posted and Saugata is
busy with his own projects. I also came across one commercial model which
didn't have any bulky transformer but only small ferrite ones like in smps.
I think I sent my block diagram to Saugata. I have changed OS in my PC and
it is difficult to locate it but I will get and put it here.
My idea was to have inverter with output switched by fast relay for crossover. Also if we don't use relay and instead use directly take out output
from inverter and meanwhile have heavyduty charger, we get cheapest
online UPS. For this there can't be output transformer and so output has to be HalfBridge type with centre tapped power supply. To get this advantage
we have to put premium on the Mosfet/IGBT voltage.(Require withstand voltage atleast 800 to 1000V) but that is better than some 10Kg transformer
for 1000W type and also price about 1000-1200/-.
I am also having one inverter with high frequency chopping but its output is
50Hz and so transfomer is very bulky.
Now I pray that sooner or later Saugata will tell us about new design !!!