Effect of Load Variation on a Voltage-Source Grid-Connected Inverter for a Solar Photovoltaic System

Abstract

Voltage source grid connected inverter (VSI) of 250 kW has been designed and simulated to be synchronized with a grid of 33 kV using a new designed control unit capable of controlling a photovoltaic (PV) system on both DC and AC sides. The control unit is capable of performing maximum power point tracking technique (MPPT) and DC voltage regulation at the DC side. On the AC side, it controls the pulse width modulation (PWM), current regulation and the phase lock loop (PLL). The design has been performed by preparing the inputs, forming the mathematical equations and simulating them via MATLAB/Simulink package. Results showed that the controller is capable of managing load variation effects on DC side of the PV system. Several changes have occurred on the AC side due to the load variation. A detailed analysis of the results is presented and discussed.