Enhanced PLL-less grid synchronization algorithm amidst unbalanced and distorted three-phase grid conditions

Manish Kumar, Raj Kumar Jarial, Anant Kumar Verma, Ravindra Nath, Miguel Torres, Catalina González-Castaño, Pedro Roncero-Sánchez

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Fast and precise tracking of grid voltage attributes is essential for the smooth and reliable control and operation of grid-side converters. The synchronous reference-frame phase-locked loop (SRF-PLL) approach is commonly used for this purpose, although it has issues related to the stability limit and sluggish transient response. Consequently, PLL-less grid synchronization approaches are becoming increasingly prevalent. In this context, in the present paper, a discrete Fourier transform-based band pass filter (DFT-BPF) is designed in the prefiltering stage for the purpose of extracting the fundamental frequency positive sequence component (FFPS) from unbalanced and distorted grid conditions. Despite being widely used, the SRF-PLL is struggling with stability issues and demands tedious tuning effort. For this objective, a simple frequency estimator has been developed, which is capable of accurately estimating the fundamental frequency. Additionally, a curve fitting based error correction technique is employed to adaptively estimate the amplitude and phase-angle of the fundamental component without using frequency feedback loop. The experimental results validate the efficacy of the proposed scheme.

Original languageEnglish
Article number108926
JournalInternational Journal of Electrical Power and Energy Systems
Publication statusPublished - Jun 2023


  • Amplitude estimation
  • DFT-based band pass filter
  • Frequency estimation algorithm
  • Phase estimation
  • Three-phase grid voltage

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering


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