Variable Frequency Control of MPTT using Two-Stage Grid Converters -Integrated Photovoltaic System

Abstract

In this paper, a cascade control technique implied for a three-phase grid-tied photovoltaic system, has been proposed. This last comprises of a PV generator, a DC/DC converter, an inverter and an electrical grid. In this structure, a new control strategy using the simplified sliding mode technique is developed for the inverter. While the boost converter control strategy has two objectives, namely, the control of maximum power by injecting the power into the grid employing the Perturb and Observe (P&O) technique and for the purpose of controlling the chopper at its maximum efficiency, the switching frequency is generated by estimating voltages and currents from the DC/AC converter. The proposed control adjusts well to the cascade control strategy. Simulations were performed thanks to Matlab / Simulink and that in aim to validate the robustness of the employed techniques for different operating states, such as the irradiation and the temperature variation.