Analysis in DSC-PLL grid synchronization method under grid frequency variation

In this paper, a new frequency adaptive DSC-PLL is proposed to improve the grid synchronization when the grid voltage is polluted by harmonics, unbalanced conditions and frequency deviated circumstances. A design method for the proposed PLL adaptive to input frequency variation is discussed, and the frequency adaptive DSC-PLL is evaluated by simulations to show their capability for detecting different harmonic components in a highly polluted grid conditions. Simulation results show the significant effects that mitigate harmonics, unbalance components and detect frequency error through the proposed PLL.