Control of Solar PV Arrays Based Microgrid Intertied to a 3-Phase 4-Wire Distribution Network

This article presents a multiple solar photovoltaic (PV) array based microgrid (MG) integrated into a 3-phase 4-wire distribution network. The main voltage source converter (VSC) and ancillary VSC's dc links are assimilated to PV arrays with maximum power point tracking. The main VSC operates with current control in a grid interfaced mode. However, at grid interruption, voltage control is utilized in an autonomous mode as a grid forming inverter, which sustains frequency and voltage across point of common coupling (PCC) for continuous power to loads. The ancillary VSC operates in current control. The feed-forward powers of PV arrays in VSCs current control improve MG dynamic behavior. MG's satisfactory behavior is achieved for changes in solar insolation and load, load unbalances, and neutral current compensation in MATLAB, and is authenticated in hardware in loop via a real-time controller, i.e., OPAL-RT (OP4510) with RT-LAB environment. The MG has the capability to sustain islanding and its mode transitions operation is seamless. The grid current total harmonics distortion (THD) and autonomous mode's PCC voltages THD are found to adhere to standard IEEE-519-2014.