Performance enhancement of grid-forming inverter-controlled PV systems: A comparative study with and without battery energy storage under intermittent and unbalanced load conditions
Muhammad Akbar Syahbani, Makbul A.M. Ramli, Prisma Megantoro, Alfananda Ardiansyah, Intan Dwi Cahyani, Noer Fadzri Perdana Dinata, Rifqi Firmansyah, Muhammad Zohri, Firmansyah Nur Budiman
Abstract
The integration of renewable energy provides an alternative solution for transitioning to sustainable energy sources. However, differences in characteristics between renewable energy systems and the grid create challenges during integration. Grid-Forming Inverter (GFMI) control enables renewable systems to emulate inertia, improving their response to load changes. However, research on GFMI implementation under intermittent and unbalanced conditions remains limited. This study investigates GFMI with NPID droop control for integrating PV systems with the grid under such conditions. It also compares PV integration with and without Battery Energy Storage Systems (BESS) to determine optimal performance. Solar intermittency data were obtained from real weather station measurements and imported into MATLAB Simulink, while unbalanced loads were configured with a high Voltage Unbalance Factor (VUF) of 73,6% and a Current Unbalance Factor (CUF) of 73,6%. Without BESS, the conditions led to increased harmonic distortion with a THD of 6.27%. However, with BESS, voltage stability improved significantly, THD was minimized to 3.27%. Additionally, PF improved, maintaining values above 0.8 in all scenarios. The system also demonstrated better active power regulation, especially when BESS was included. These findings highlight the necessity of BESS in renewable energy integration to enhance grid resilience against intermittency and load imbalances, ensuring stable voltage, improved power quality, and reduced harmonic distortion.