Intelligent Transition Control Approach for Different Operating Modes of Photovoltaic Inverter

The increasing distributed generation (DG) systems and their integration with the utilities has complexed the operation of the power system network by subjecting them various abnormalities. Numerous studies are aimed to explore the ability of an inverter in a DG system to operate in standalone (SA) mode during the abnormal operation of the utility or when it is scheduled for maintenance. In this paper, a grid condition monitoring based transition approach is proposed by developing a hybrid control strategy to control the photovoltaic (PV) inverter operating in the grid-connected (GC) mode. In the case of Intentional or unintentional islanding conditions, the PV is disconnected, and voltage loop-based control is implemented for controlling the PV inverter in the SA mode of operation. The switching between the control strategies of GC and SA is performed by the central controller ensuring a smooth transition and continuous power delivery to the load. For validating the claims, a 4 kWp PV system is designed on MATLAB Simulink. The system is operated in both SA and GC mode of operation and the result depicts smooth transition without any transient peaks or harmonics.