An Efficient Technique Using Modified p–q Theory for Controlling Power Flow in a Single-Stage Single-Phase Grid-Connected PV System

In this paper, an efficient power conditioning unit is presented for a single-phase grid-connected photovoltaic (PV) system incorporating both maximum power-point tracking and current control algorithms in a single-stage. Modified p-q theory is applied to derive the reference signal for a hysteresis band current (HBC) controller so that the active and reactive power sharing between the PV system and the grid can be controlled independently. Enhanced stability during the internal dynamics, caused by the variations in PV generation and load conditions, is the prime aspect of the controller. The performance of the proposed p-q theory correlated HBC controller is evaluated against tracking of maximum PV power and compensation of load reactive power under the changeable atmospheric and load conditions, and also compared with the widely used conventional proportional resonant controller to justify superiority. Simulation and experiment are carried out under variable weather and different load conditions to validate acceptability of the proposed control scheme.