Fuzzy grey sliding mode control for maximum power point tracking of photovoltaic systems

This paper proposes a fuzzy-grey sliding-mode control (FGSMC) strategy for maximum power point (MPP) tracking in photovoltaic (PV) systems. The problem to be addressed is that the linear reaching law in a previous SMC design has limited reaching speed if control saturation is to be avoided. Hence, a nonlinear reaching law is proposed by means of fuzzy-logic control which employs as inputs the sliding function, and its predicted forward difference provided by a grey-prediction algorithm. Control design is performed on an averaged system model, whereas the performances of FGSMC and SMC are compared in simulation on both the averaged model and the true switching PV system.