Enhanced Third-Order Generalized Integrator-Based Grid Synchronization Technique for DC-Offset Rejection and Precise Frequency Estimation

An enhanced third-order generalized integrator (TOGI) method has been proposed for the estimation of grid frequency and the synchronizing signals. The proposed method precisely estimates grid frequency and synchronizing signals in the presence of high harmonic content, phase change, frequency change, noise, and DC-offset in the grid voltage. A robust frequency estimator based on three consecutive sampling method has been integrated with TOGI algorithm for accurate frequency estimation. The proposed technique gives zero steady-state error in case of frequency estimation under different grid voltage conditions. This paper demonstrates the developed enhanced TOGI technique for synchronization in a single-phase system. The efficacy of the proposed algorithm has been tested and analyzed in MATLAB/Simulink and verified with experimental results.