12V DC to 220 V AC

Hello to all ... curently I'm trying o build a home made UPS but I'm stuck at the 12VDC to 220VAC (50Hz) inverter (is inverter the correct word?) of about 500 Watt. Can anyone lent me a hand? I'm using protel DXP to design it.I can send the schematics to anyone interested.

P.S. can anyone tell me where I can find protel library files to download? (for protel DXP)

In the Mohan power electronics book, there is a very good discussion about how to build your inverter (which is the proper term). Note that going from 12->220 is going to be rather inefficient. The higher your low side voltage, the easier it is. 500W is going to be about 41 amps, that is alot of power to draw from a 12V battery -- and that is assuming no loss in the inverter.

In any case, most inverters do not generate pure sine waves, instead they generate a pwm signal which is created by using a sine and triangle wave fed through a pair of comparators. I can post a signal plot if that will help (I dont have one ready right now).