Enhanced Grid Synchronization Technique Based on Frequency Detector for Three-Phase Systems

Abstract

An adaptive cascaded delayed signal cancellation (CDSC) method relying on a simple frequency detector is combined with a third-order function for three-phase grid synchronization application. In this article, the proposed synchronization technique shows a high degree of insensitivity to harmonics at both nominal and off-nominal frequency environments. When compared to a similar method relying on adaptive CDSC and phase-locked loop (CDSC-PLL), the proposed technique generates alike results but demands less computational effort due to avoiding real-time evaluation of computationally demanding trigonometric functions and square root operation. Moreover, unlike the CDSC-PLL method, the proposed one eliminates the interdependent loops exist between the phase and frequency estimation, thus a simpler tuning process is achieved. In addition, the proposed method stays away from the tuning of the loop filter in the PLL by removing the phase loop. The usefulness of the proposed method is established by both simulation and experimental results.