Adaptive backstepping control of a DC-DC converter in photovoltaic systems

This paper presents a new nonlinear control method to regulate the voltage at the output of a DC-DC converter so as to achieve the maximum power point (MPP) of a photovoltaic (PV) system. The proposed adaptive backstepping controller of the system, based on Lyapunov functions to ensure locally stability, is applied to a buck-boost converter. A regression plane is used to initialize reference voltages and to make a modified perturb and observe method (P&O) faster, avoiding local maximum. Therefore, the maximum power extraction of the PV system is guaranteed. This system is grid-connected, thus, a DC-AC converter is connected to the buck-boost converter. The inverter supplies AC current in the point of common coupling (PCC) of the electrical network. The performance of the developed system has been analyzed by means a simulation platform in Matlab/Simulink.