Square to Sine Wave converter

There must be a reason why sine wave inverters are expensive..... Pehaps you
should find out why.

It may be the expensive of the square to sine coversion may be more
expensive than a direct pruchase of a sine wave inverter... after
considering the design, labor and material costs.

Aaah!   Google gave lots of hits... including this one.
http://www.elci.tuc.gr/downloads/Kalaitzakis/J.19.pdf

Seems the complexity of design.... and cost of parts are what you are paying
for...... If I spent years on a design.... I wouldn't give it away for free.

JG