Point of common coupling (PCC) voltage control of a grid-connected solar photovoltaic (PV) system

In future low voltage grids, with multiple inverter interfaced sources connected, voltage regulation may become a necessary task. The potential exists for inverter interfaced sources to be deployed to regulate the voltage at the point of common coupling (PCC) of each inverter interfaced sources. The PCC voltage regulation is attainable with inverter interfaced sources by dynamically controlling the amount of reactive power injected to the power distribution grid by individual systems. In the current research, a closed-loop controller is proposed to regulate the PCC voltage of a solar photovoltaic (PV) system that is connected to a single-phase power distribution feeder (with R to X ratio greater than 1). The plant model of the PCC voltage controller of the PV system is derived considering both reactance and resistance of the network to which the PV system is connected. Three different compensators are evaluated to identify a suitable compensator for the closed-loop PCC voltage controller to regulate the PCC voltage at a given reference voltage. Simulation studies and experimental verification confirm that the theoretical approach taken to derive the control plant model of the PCC voltage controller is accurate and the procedure that is followed to design the controller is robust. The control design procedures illustrated in the current research leads to a PCC voltage control system with acceptable dynamic and steady state performance.