A phase lead-lag synchronous PLL for grid synchronization of a single phase inverter

Abstract

The phase lead-lag synchronous PLL for grid connection of a single-phase inverter is proposed. The method employs tuned filters that advance and delay phases by ±45 degrees with respect to the phase of the grid. Both orthogonal signals are fed into the Park's transformation. The quadrature-phase signal is regulated to zero using a PI controller which its output determines the frequency. The phase is obtained by integrating the frequency. The proposed method is validated by simulation using MATLAB/Simulink. It is implemented on a microcontroller and tested with a programmable AC source. The results confirm the viability and effectiveness of the method.