A Novel Hybrid Global MPPT Technique for Grid connected PV Systems

Abstract

This paper proposes a novel Global Maximum Peak Power Tracking Technique in grid connected photo voltaic (PV) systems. It aims to achieve higher tracking accuracy, improved efficiency and better response time while tracking Maximum Power Point (MPPT) during both uniform and partial shading conditions. A voltage Compensator (VC) is selected here for the dc-dc stage, followed by a three-phase two level SPWM VSI for grid connection. The proposed global MPPT algorithm tracks global peak power point (GMPP) during partial shading while minimizing the grid power fluctuation during GMPP search, ensuring the tracking accuracy of more than ninety nine percent. The system is also capable of by-passing the VC to ensure minimum power loss when the available PV string MPPT voltage is high enough to ensure inverter operation. Nonetheless, the MPPT algorithm is also sensitive to any change in PV panel insolation and ensures that the new GMPP is tracked when such a scenario is encountered. The proposed algorithm and control methods are implemented in MATLAB/Simulink environment for various partial shading scenarios.