MPPT and Unity Power Factor Achievement in Grid-Connected PV System Using Nonlinear control

Abstract

This work deals with the problem of controlling single-phase grid connected photovoltaic system. The system consists on a photovoltaic (PV) panel, a boost power converter and a single phase inverter connected to the grid. The control objective is fourfold: (i) asymptotic stability of the closed loop system, (ii) maximum power point tracking (MPPT) of PV module (iii) tight regulation of the DC bus voltage, and (iv) unity power factor (PF) in the grid. A nonlinear controller is developed using feedback linearizing technique based on an averaged nonlinear model of the whole controlled system. The model accounts, on the one hand, for the nonlinear dynamics of the underlying boost converter and inverter and, on the other, for the nonlinear characteristic of PV panel. It is formally shown, through theoretical analysis and simulation results, that the proposed controller does achieve its objectives.