Integration of single stage solar PV system to grid under abnormal grid conditions

This paper deals with the modelling and design of a single stage solar PV (Photovoltaic) grid integrated power generating system using fuzzy logic based maximum power point tracking (FL-MPPT) with a decoupled current controller based control algorithm under abnormal grid conditions. The system includes solar PV array, FL-MPPT, two level VSC connected to three phase AC grid. A FL-MPPT is used to track maximum power from solar PV array which gives reference voltage and power to decoupled current controller. Fuzzy logic control provides a fast response without fluctuations and is able to adjust the step size depending on the varying conditions. The solar PV system transfer maximum energy to the grid at nearly unity power factor. Simulated results validate the design and control algorithm under dynamic conditions of varying solar insolation, sudden voltage sag and swell conditions.