A Novel Variable Time Delay FLL Based Estimation of Positive and Negative Sequence Components of Grid

A simple and fast technique for the estimation of positive and negative sequence components under unbalanced grid conditions is proposed. Grid synchronization is achieved by the application of instantaneous symmetrical components method on stationary and orthogonal αβ reference frame. In this paper, the frequency dependent variable time-delay based algorithm is used to generate the quadrature signals used on αβ reference frame. The frequency adaptive characteristic of the time-delay method is achieved by SOGI-FLL (Second Order Generalized Integrator Frequency Locked Loop). The proposed technique is simulated using MATLAB/Simulink and conducted experimentally as well.