Adaptive PI + VPI Harmonic Current Compensation Strategy under Weak Grid Conditions

With the increase of penetration rate renewable energy power generation in system, grid gradually tends to be weak. Under scenario nonlinear load connecting weak grid, grid-side voltage will produce unbalance, distortion and frequency deviation due influence large internal impedance, insufficient inertia, three-phase current unbalance harmonics grid. The operation active filters (APF) under above conditions can lead significant degradation harmonic compensation performance. An adaptive proportional integral (PI) + vector PI (VPI) strategy for a APF is proposed use complex consists an notch filter based synchronous phase-locked loop (ANF-PLL) VPI control method. In this strategy, series lattice are introduced improve accuracy phase estimation condition range deviation. Then information used Park transformation detection update law parameters. A tracking controller with resonant constructed, which gain point ensure that maintain best performance conditions. Finally, simulation experimental results indicate ANF-PLL shows better than conventional methods, presented paper achieves improvement compared Fixed VPI/SRF-PLL VPI/NF-PLL strategy.