Adaptive robust maximum power point tracking control for perturbed photovoltaic systems with output voltage estimation

• The variations of irradiance and cell temperature are taken into account.
• The upper bound of perturbations is not needed to be known.
• The output voltage is not required to be sensed.
• Estimating the output voltage, two adaptive robust MPPT algorithms are proposed.
• Robust tracking convergence is ensured, using the Lyapunov stability theorem.

The problem of maximum power point tracking (MPPT) in photovoltaic (PV) systems, despite the model uncertainties and the variations in environmental circumstances, is addressed. Introducing a mathematical description, an adaptive sliding mode control (ASMC) algorithm is first developed. Unlike many previous investigations, the output voltage is not required to be sensed and the upper bound of system uncertainties and the variations of irradiance and temperature are not required to be known. Estimating the output voltage by an update law, an adaptive-based H∞H∞ tracking algorithm is then developed for the case the perturbations are energy-bounded. The stability analysis is presented for the proposed tracking control schemes, based on the Lyapunov stability theorem. From a comparison viewpoint, some numerical and experimental studies are also presented and discussed.