Plz give proper controller diagram if possible...i just want in islanded mode of microgrid...i want to track frequency deviations due to load changes... Becoz in VF control we always give const freq toh abc to dq block...
Are you sure we always give the constant frequency? As far as I understand, the inverters use phase locked loop to measure the point of common coupling frequency.
Have a look at the review papers for more clarification:
The grid-feeding should be perfectly synchronized with the ac voltage at the connection point, in order to regulate accurately the active and reactive power exchanged with the grid.