Control of Multi-Converter Based Microgrid for Unified Power Transfer to Local Loads and Charging Station in Unusual Grid Conditions

This work presents a common AC bus microgrid topology designed to supply continuous energy to localized loads and plug-in electric vehicles (PEVs). The topology incorporates solar photovoltaic (PV) array as renewable energy sources, along with energy storage solutions to effectively address operational uncertainties. Distributed energy resources are connected through dedicated DC-AC converters, enabling efficient power distribution to a centralized AC line. Primary contribution of this work is operation of a proposed AC microgrid topology that guarantees reliable power source to loads through application of power flow control logic, while effectively mitigating power quality issues. Power electronics circuitry integrated with renewable energy sources and the grid encounters power quality issues at point of common coupling. To address these power quality challenges, a cascaded distinctive gain-based second-order integrator, coupled with a harmonic sequence extractor, is employed to isolate fundamental components of grid voltages. Additionally, a power flow controller logic is implemented to manage irregularities on both source and load sides, establishing criteria for optimal operational modes. Presented topology and control strategies are validated through laboratory testing using a hardware prototype, demonstrating the effectiveness through empirical test results.