Modeling of Two-Stage Photovoltaic Inverter with Grid Connected and Islanding Operation

Abstract

This work implements a photovoltaic single-phase grid-connected converter. The voltage output is regulated by the power inverter control circuit in system operation. The converter control loop observes the voltages and currents of the power system network and looks at the frequency and phase angle of the inverter using PLL (phase-locked loop). In islanding mode, the inverter controller regulates the voltage and frequency of the output of the converter. The inverter is integrated into a DC bus, which is coupled to a photovoltaic array through a DC-DC boost converter. In the connected mode of the network, the PV operates at maximum Power Point, whereas, in the island mode, the PV operates in the voltage regulation mode. To eliminate the high-switching-frequency harmonics component, an LCL filter is used. MATLAB simulation is used to verify the system implemented.