Standard SOGI-FLL and Its Close Variants: Precise Modeling in LTP Framework and Determining Stability Region/Robustness Metrics

In recent years, single-phase frequency-locked loops (FLLs) are gaining more popularity as a signal processing and synchronization tool in wide variety of engineering applications. the power energy area, basic structure designing majority available FLLs is second-order generalized integrator-based FLL (SOGI-FLL), which nonlinear feedback control system. This nonlinearity makes SOGI-FLL analysis complicated. To deal with this problem, some attempts to derive linear models for have been made very years. The models, however, not able accurately predict dynamic behavior, stability region, robustness metrics SOGI-FLL. situation even worse close variants because them no model at all. Filling these gaps research main goal article. end, structural relationship among its identified first. Based on information deriving time-periodic (LTP) recently proposed extended SOGI-FLL, LTP standard obtained. accuracy assessment discussion about their limitations, performing using other contributions