Conversion From Square To Sine Wave...(Filter Design)

[Airian_007]

Hi,
I need to if there is any simple methode to convert a square wave to sine wave of a modified sine wave to pure sine wave for an inverter.
i dont have prior knowledge of filters as i searched on google and there are some LC type filters i am familiar with Inductors and capacitors but never used as filters before.
i have also heard that transformer at step up stage also acts as filter and gives sine wave plz help in this regard.
Thanks In Advance.

 

[crutschow]

Depends upon how much distortion you can tolerate in the sine-wave.

What is the form of the "modified sine wave"?

 

[Airian_007]

I need pure sine wave no discrepancies....
ok i have a c code for spwm and its working fine and at output stage i am using a low pass filter and results are very good i am getting a good sine wave but the problem is i am using RC filter but in actual i dont know what values of RC should be used i mean their power ratings and i have seen some LC filters but i am struck in designing one as it will be working on 230VAC so i am little confused about it.
thanks

 

[Airian_007]

One More thing i am interested in designing SMPS inverter to reduce size of transformer i want to know like usual 50 or 60 Hz transformer..ferrite core can be used in reverse? what if i get one from old laptop power supply and use it in reverse to get 310vdc?