how to design a 100W grid connected pv inverter using pll

[sanjoy62]

hello everyone i m new here.i m badly in need of a design of 100W grid connected pv inverter using pll bcoz it is my project to complete graduation and have to submit within 30 days.

 

[RCinFLA]

Phase lock algorythms for grid tie inverter should have a very low bandwidth and resistance to false crossing trigged by transient spikes common to power grid.
Bandwidth can be so low that reaction is measured in tens of seconds to minutes. Real grid frequency changes very very slowly so anything that tells you otherwise is always incorrect.

There is also absolute spec limits based on UL1741 spec such as 60 hz with -0.7hz/+0.5hz absolute tolerance. Engagement outside this range so not be done.

A digital early/late zero crossing detection can be used with a long counter to filter the result over the long time period. Once locked there can be a time window gating opening added to the early/late zero cross detector to further minimize pertubations due to transients.