An Improved Grid Synchronization Method of Grid-Interactive Power Converter System During Distorted Grid Conditions

Abstract

In recent years, integration of renewable energy systems (RES) into the electrical grid has acquired the attention of researchers across the globe. Grid parameters such as frequency, voltage and phase angle must be continuously monitored to overcome the problem of synchronization, as gridside converters usually interact with the electrical grid. In this paper, an enhanced sliding Goertzel discrete Fourier transform (SGDFT) based phase locked loop (PLL) for grid synchronization of grid-interactive power converter system was proposed. With the proposed enhanced SGDFT PLL based frequency estimation, a robust frequency tracking capability with a very fast transient response under distorted grid conditions are achieved. The complete analytical model of Proposed PLL is analyzed and compared with existing PLLs such as Enhanced Prefilter Moving Average Filter Type 2 PLL (EPMAF Type 2 PLL), Harmonics Interharmonics DC Offset PLL (HIHDO PLL), SGDFT PLL. The proposed work has been analyzed in MATLAB/Simulink <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> environment and the obtained results are suitable for harmonic mitigation and DC offset rejection. Finally, the Hardware in Loop (HIL) simulation of different PLLs are investigated by dSPACE 1104 environment to verify the effectiveness of the proposed study.