An Improved Hybrid Prefiltered Open-Loop Algorithm for Three-Phase Grid Synchronization

• Published in: IEEE transactions on industrial electronics (1982) Vol. 68; no. 3; pp. 2480 - 2490
• Main Authors: Verma, Anant Kumar, Jarial, Raj Kumar, Roncero-Sanchez, Pedro, Ungarala, Mohan Rao, Guerrero, Josep M.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.03.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Amplitudes; Bandpass filters; Delays; Demodulation; Electric potential; Frequency estimation; grid voltage demodulation; Harmonic analysis; moving average filter (MAFs); Phase locked loops; Power harmonic filters; Rejection; Resonant frequencies; Response time; Synchronism; three-phase system; Time factors; Transient response; Voltage
• ISSN: 0278-0046; 1557-9948
• DOI: 10.1109/TIE.2020.2975470

In this article, a robust three-phase grid synchronization technique has been proposed for rapid detection of fundamental frequency, phase, and amplitude. The widely accepted phase locked-loop (PLL) algorithms possess complex architectures and require tedious tuning process for attaining a good stability margin. In order to surpass the shortfalls of PLL algorithms, a computationally efficient, stable, and open-loop scheme has been reported in this article. A novel two consecutive samples based frequency estimator is developed for fast detection of the fundamental frequency. Moreover, an efficient hybrid prefiltering approach is implemented based on the demodulation of the grid voltage signal. Additionally, the combination of a delayed signal cancellation operator and a band-pass filter allowed rapid rejection of dc-offset and harmonics, respectively. In the event of a grid voltage imbalance, the instantaneous symmetrical component method is a rescuer for the rejection of the fundamental negative sequence component without any delay. Subsequently, overall transient response time of the scheme is observed to be improved. On the other hand, the fundamental positive sequence component facilitates the estimation of amplitude and phase angle information. Importantly, the dynamic performance of the proposed scheme has been experimentally validated in presence of various grid disturbances.