Optimal Design of Improved Dual Second-order Generalized Integrator-Frequency Locked Loop
Aiming at the problem of synchronizing signal detection under non-ideal conditions of power grid,an im-proved dual second-order generalized integrator is proposed based on the analysis of the dynamic performance of the tra-ditional second-order generalized integrator model under the condition of DC components and high-order harmonics.The control structure of the frequency-locked loop is given,the theoretical analysis of its dynamic performance is given,and an improved three-phase second-order generalized integrator and the control model of the frequency-locked loop are pro-posed.The simulation results show that compared with the traditional control structure,the performance of the improved control model is improved by 94.48%,85.17%and 89.73%respectively under the characteristic sub-harmonic,DC compo-nent and inter-harmonic disturbances.