MPPT Controllers Based on Sliding-Mode Control Theory and Fuzzy Logic in Photovoltaic Power Systems: A Comparative Study

In this chapter we will deal with a comparative study between two control methods for maximum power point tracking (MPPT) algorithms in photovoltaic (PV) systems. The two MPPT controllers considered in this chapter are: the Fuzzy Logic Controller (FLC) and the Sliding Mode Controller (SMC). The MPPT controller based on the fuzzy-logic-algorithm uses directly the DC-DC converter duty cycle as a control variable and it provides a fast response and good performances against the climatic and load changes. The SMC exhibits a very fast response for tracking the maximum power point (MPP) for photovoltaic systems. The input parameters are the voltage and the current, the duty cycle is used to generate the optimal MPP under different operating conditions. Simulation results show that both algorithms can effectively perform the MPPT hence improving the efficiency of PV systems.