A frequency adaptive technique for accurate estimation of single-phase grid voltage fundamental parameters

This paper proposes a frequency adaptive quadrature signal generator (QSG) for estimating the single-phase grid voltage fundamental parameters such as amplitude and frequency. The QSG relies on the anticonjugate decomposition (ACD) and the cascaded delayed signal cancellation (CDSC) strategies (QSG-ACDSC), and it is used to track the fundamental voltage amplitude. The frequency adaptive capability of the QSG-ACDSC is obtained by a frequency estimation algorithm based on the estimated fundamental orthogonal voltage waveforms. The technique is relatively simple and it can provide accurate estimation of fundamental voltage amplitude and frequency. The proposed technique shows less sensitivity to the presence of harmonics as compared to the QSG based on a second order generalized integrator and a frequency-locked loop. Simulation results are presented to verify the performance of the proposed technique.