A Comparative Analysis of SRF-PLL and EPLL for Grid Connected Converter

This paper analyze different PLL techniques in synchronization. Accurate grid phase angle and frequency tracking are crucial, especially in imbalances. In this study, the Enhanced PLL (EPLL) incorporating a filter is investigated and compared with the Synchronous Reference Frame (SRF-PLL), both with and without filters. The paper introduces mathematical modelling that examines multiple parameters, encompassing frequency response and phase error under various unbalanced scenarios. Furthermore, the investigation extends to analyzing the Second Order Generalized Integrator (SOGI) and Cascade Second Order Generalized Integrator (CSOGI) PLL designs. They are implemented within a grid system to validate the proposed PLL topologies. Notably, the EPLL with a filter performs better in mitigating issues such as amplitude fluctuations, DC offset, and the presence of the third harmonic. This study contributes to advancing the understanding of PLL techniques for synchronization, offering insights into their performance characteristics and highlighting the benefits of the EPLL configuration with a filter.