Advanced Control Strategy With Voltage Sag Classification for Single-Phase Grid-Connected Photovoltaic System

This article develops a fault ride-through control strategy for achieving low-voltage ride through in single-phase grid-connected photovoltaic (PV) systems (GCPVS). The proposed control system adapts a neural network classifier for islanding classification and model predictive control for achieving the control of the two-stage PV system. This control scheme takes advantage of the nonlinear nature of the power converters and develops a cost function-based approach to achieve fast and efficient control. In addition, the proposed controller provides voltage support to the grid during voltage sags by injecting minimum reactive current within the threshold. The operation of the proposed control strategy is verified by performing simulation tests on a 4 kW GCPVS by creating a sag type of fault in the utility. Further, laboratory experiments were carried out with the developed controller. The results ensure that the proposed control system adheres to the grid requirements by enabling voltage support during grid faults.