Grid-Connected Phase-Locked Loop Technology Based on a Cascade Second-Order IIR Filter

The moving average filter-based phase-locked loop (MAF-PLL) can obtain grid synchronization signals accurately under adverse conditions with a large amount of harmonics due to the high filtering capability MAF. However, MAF-PLL cannot achieve fast dynamic response in case frequency drift, phase angle steps, and unbalanced voltage sag. MAF is essentially an FIR filter, its performance hard be adjusted. To address this issue, paper proposes alternative consisting set cascading second-order IIR filters (CIIRF). Based on MAF, CIIRF introduces multiple zeros poles from zero–pole replacement perspective, by changing position poles, filter improve anti-interference ability PLL based (CIIRF-PLL) presence frequency-adaptive scheme also proposed. Simulation experimental results show that CIIRF-PLL track jumps, injection, sag has good steady-state performance.