A Unified mode transition between Grid-tied and Islanded modes in a RBVSG using Uninterrupted Switching Scheme

Abstract

This article presents a three-phase single-stage photovoltaic energy conversion system (PECS) that connects residential buildings (RB) to the power grid. Unlike the traditional use of RBs as power consumers, this system treats RBs as power generators. However, PECS lacks inertia, making integrating with the power grid challenging. Addressing the issue, the virtual synchronous generator (VSG) technique is used to add inertia to the PECS-based system. The main focus of the article is to enhance the grid's interactivity by introducing Residential Building Virtual Synchronous Generators (RBVSG). RBVSG is tested under distorted grid voltage and varying load conditions, proving its ability to provide distortion-free, balanced grid currents with adjustable power factor while maintaining power quality. In low solar power availability, RBVSG continues to enhance power quality and imports power from the utility grid to meet local demands. Furthermore, under such conditions, the PECS power reduces or has a huge deviation in voltage; the dc-link voltage adjusts adaptively by following the variations in grid voltage, thereby increasing RBVSG system reliability and reducing operating losses. The system's efficacy is checked in MATLAB/Simulink platform and experimentally validated by a laboratory prototype. © 2023 IEEE.