Abstract

Wide acceptance of solar energy as a viable alternative to fossil fuels has lead to integration of solar generation systems to the modern power grid. Added to high capacity solar generating units, distribution level solar generation has gained importance and popularity. To effectively implement intelligent systems that feed household generated surplus power to distribution feeder network, modeling and simulation of the grid tied solar system is of high importance. The paper models a 5kW domestic roof top solar grid tie system connected to 230-240 V single phase grid. The work proposes a two level boost topology with an efficient output voltage control system that synchronizes the phase, frequency and voltage of the inverter with the grid. The MPPT DC-DC converter controlled by Incremental Conductance (INCCOND) extracts maximum power while the second level DC-DC converter controls the DC link voltage according to the Grid voltage changes to effectively regulate the inverter output voltage. The developed model has been implemented and simulated using MATLAB/SIMULINK. Dynamic grid voltage changes have been imposed to evaluate the performance of the voltage controller and the two level boost converters. The results show that the output power to the grid not only adheres to the power quality level imposed by IEEE standard 519 but also a fast dynamic response to voltage, phase and frequency changes have been obtained.