A new DSC-PLL using recursive discrete fourier transform for robustness to frequency variation

In this paper, a new DSC-PLL (Delayed Signal Cancellation Phase Locked Loop) with FLL (Frequency Locked Loop) based on RDFT(recursive discrete fourier transform) method is proposed for coping with frequency variation. This method shows significant performance improvement for detection of fundamental positive sequence component voltage when the grid voltage is polluted by grid harmonics and frequency variation. The frequency detection technique of DSC-PLL tracks frequency drift by the RDFT. These compensation algorithms can correct for discrepancies of changing the frequency within maximum 28ms and improve traditional DSC-PLL. To verify feasibility of the proposed DSC-PLL, Matlab/Simulink results show good agreement with the analysis.