Integrated Fault-Diagnoses and Fault-Tolerant MPPT Control Scheme for a Photovoltaic System

In this paper, a Lyapunov-based control concept is presented that works on certainty equivalence principle. The considered SISO system is affected by matched uncertainty, which is effecting output power of PV system. Resorting to the certainty equivalence principle the controller exploits advantages of both the sliding-mode and the adaptive control methodology to form new control strategy called certainty equivalence super twisting algorithm (CESTA). CESTA is used to diagnose and tolerate the fault effecting the performance of MPPT controller. It is validated that the gains of the discontinuous control action are reduced remarkably when compared with conventional sliding mode techniques. Based on these lower gains maximum power is extracted from PV array in the presence of matched uncertainty. The efficiency of the presented concept is demonstrated in detail, using results of numerical simulations.