Adaptive Observer-based Control Strategy for Maximum Power Point Tracking of Uncertain Photovoltaic Systems

Abstract

This work presents an adaptive observer-based control strategy for maximum power point tracking (MPPT) of uncertain photovoltaic (PV) systems. On the one hand, the PVG output voltage and/or current measurements are needed for MPPT techniques and controllers design and, on the other hand, the PV arrays have to be installed in a site that profits from good daily sunshine. This obviously leads to difficulty of PVG output current and voltage measurement if ever such a site is at great distance from the converter. Furthermore, the MPPT control accuracy could be significantly affected due to the cable parameters if only voltage and current measurements on the converter side of the cable are instead used. To overcome this issues, an adaptive extended Kalman–like observer providing estimates of PVG output current and voltage regardless of cable resistance and inductance deviations, is first designed. Afterwords, a backstepping controller is synthesized to ensure the MPPT objective. The designed adaptive observer-based MPPT control convergence is formally analyzed and its effectiveness in compensating for cable parameters uncertainties on the MPPT accuracy is validated through numerical simulations.