Improved Gaussian Filter Based Solar PV-BES Microgrid With PLL Based Islanding Detection and Seamless Transfer Control

This article presents an improved Gaussian filter with phase-locked loop based grid monitoring and seamless transfer control for solar photovoltaic-battery energy storage (PV-BES) based microgrid with improved power quality. The PV-BES microgrid comprises of a PV array and a battery, interfaced to the utility through a voltage source converter, and performs multiple tasks. In grid-connected mode, the improved Gaussian filter with quadrature signal generator-based second-order generalized integrator based prefiltering provides solar PV power to the nonlinear loads and the utility grid, along with providing reactive power compensation and power quality improvement at the point of common coupling. To regulate the power absorbed or discharged by the BES, a bidirectional converter is used. The PV feed-forward term enables PV power injection and also improves the dynamic performance of the system. On grid outage, the controller transits the PV-BES microgrid to standalone mode of operation ensuring uninterrupted supply to the load. The effectiveness of the controller is tested in various scenarios and is verified through experimentation. The controller has satisfied the specifications set by the IEEE 519-2014 power quality standard and IEEE 1547-2018 (revised) standard for interconnection and interoperability of distributed energy resources.