Two-Sample PLL With Harmonic Filtering Capability Applicable to Single-Phase Grid-Connected Converters

The two-sample phase locked loop (2S PLL) in single-phase digitally controlled grid-connected power converters provide synchronization with a minimal computational burden. However, the distortion of grid voltage deteriorates performance 2S quadrature signal generator. To solve this issue, article introduces harmonic filtering (HF) structure based on observers input for fundamental and selected harmonics. stability sensitivity PLL HF is analyzed. In comparison second-order generalized integrator (SOGI)-based HF, narrower bandpass, subsequent deterioration response time compensated by adapting filter gains dynamically. results obtained, both simulation experimentally, validate proposal compare its other widely adopted PLLs providing rejection capability. burden analyzed case proposals depends number use or not adaptive strategy steepest descent.