Recent interest in the integration of solar power on to the grid raises concerns about the synchronization technique.

Synchronization is a crucial problem in grid-tied inverters operation and control research indicates that frequency, phase, and amplitude of voltage are the most important parameters that need to be measured and controlled for grid-tied application.

A phase-locked loop (PLL) is a popular grid synchronization approach. Traditional PLL catches the frequency and phase through feedback loop-filter (LF) to improve steady-state capability during adverse grid conditions.