Photovoltaic-grid integrated system

This paper proposed solution for directly energizing of ac load throughout Photovoltaic Solar Array during the daytime by applying so called variable voltage tracking system (VVT). The main function of VVT is to maintain the average output chopped voltage at fixed value irrespective of solar radiation rate, in turn the chopped voltage is converted into ac voltage suitable for grid-connected loads. This solution is realized by integrating both complementary buck-boost chopper and dc to ac converter. The ac-grid contributes to the load in two cases, first when there is a power shortage during the daytime due to weak irradiation rates, and second during the night time. The power estimator unit is used to determine the grid contribution intervals. This solution excludes the use of battery bank which is the main obstacle in massive use of solar energy due to their weight, short life time, maintenance and cost. Matlab/Simulink is used to simulate the proposed model, where the obtained simulation results confirm and justify the proposed approach for further study and looking for optimized solutions for cost reduction and energy savings.