Anyone plz design a smps dc-ac (12volt dc to 220 volt ac) inverter. plz consider more then 3000watt. atleast advise me plz plz ..

 

Here's a 2KW 12v to 120v inverter: http://technology.niagarac.on.ca/people/mcsele/i2k.htm

But, I'll bet you think that you can get 3KW 220v for quite a while from a single 12v battery, right?

That's not going to happen.

Buy a gasoline, diesel, or better yet multifuel powered generator instead.

 

A bit of simple maths will show you that if your converter is 100% efficient then the battery current required at 3000W output will be 250A.

Semiconductors to reliably handle this current are big and expensive! Never mind the other components. For example, a volt drop of 1V in the semiconductor will loose 250W! So the efficiency will be well short of 100%.

This is why inverters to produce power in the region of 3kW generally work at much higher input voltages, probably 48V or at least 24V.