Hi,

My original design was based on a 18F452. Using both of the hardware PWMs and a sine weighted lookup table to modulate the PWMs at regular intervals. The interrupt routine also triggers an ADC to correct distortion on the output. So the ADC was sampled after every PWM steps. I found that the internal ADC was not giving me good results so used an external one. Now I realize that I actually complicated my design.



After the Master's Conference in Gurgaon India me and Pramod would be jointly working on a software based PWM sine wave UPS/Inverter this month. It is again a commercial project but we can sure shed some light and guide people by at least suggesting a way. A normal home UPS/Inverter does not need (at least here) a distortion free clean Sinewave. So we are restricting ourselves to the following criteria.

1. Low Cost
2. Low component count
3. Decent sinewave generation with only average variation for voltage regulation and no THD management.

Hope we successfully complete the same. We will get back here, since this is the place where we met.