D-estimation method for grid synchronization of single-phase power converters: analysis, linear modeling, tuning, and comparison with SOGI-PLL

D-estimation method (DEM) is a single-phase synchronization system, which includes a prefilter, a postfilter, an estimate producer, and a frequency feedback (FFB) loop for adapting the prefilter and postfilter to frequency changes. The DEM has a completely different structure compared to phase-locked loops (PLLs), which makes its analysis, tuning, and linear modeling rather challenging, at least for those who are not very experienced in this area. This study aims to bridge this research gap. It is demonstrated in this study that the DEM, in its simplest possible form, is mathematically equivalent to the second-order generalized integrator-based PLL (SOGI-PLL) if a certain condition holds. This equivalence, which is verified numerically and experimentally, makes the linear modeling, analysis, and tuning of the DEM quite straightforward.