The comb filter is applied to the field of grid-connected phase-locked loop. The main drawback of traditional comb filter based phase-locked loop(CF-PLL)is the slow dynamic response. The improved comb filter based phase-locked loop(ICF-PLL)is proposed by introducing the correction element. The setting method of parameters for the ICF-PLL controller is proposed based on its s-domain model. In order to improve the disturbance resisting ability of the ICF-PLL when the frequency of the power grid changes

an improved comb filter based frequency adaptive phase-locked loop(FAICF-PLL)and its digital implementation scheme are presented. Simulation and experimental results show that FAICF-PLL has good steady-state and dynamic performance for its accurate phase locking under frequency ripple

phase angle change

distorted harmonic and unbalanced voltage sag grid conditions.