Grid-connected of photovoltaic module using nonlinear control

The problem of controlling single-phase grid connected photovoltaic (PV) system is considered. 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 the backstepping design 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.