Stability analysis of grid connected PV array under maximum power point tracking

In this paper, the stability of a grid connected photovoltaic (PV) array is studied under two different maximum power point tracking (MPPT) algorithms. For the study, a 100 kW PV array connected to a grid via a voltage source inverter and a boost converter is considered. The system is modelled in MATLAB Simulink including the incremental conductance (InC) and perturb & observe (P&O) MPPT techniques. By Simulink simulation, the grid disturbances are studied under normal as well as transient conditions. The simulation results show that at normal condition the InC MPPT algorithm provides better response time and efficiency than the P&O MPPT algorithm. However, at transient condition P&O MPPT algorithm provides better recovery time than the InC MPPT algorithm. This study advocates to design hybrid MPPT algorithm such that the algorithm works effectively under both transient and normal conditions.