A Comparative Study Between Two MPPT Controllers Based on the Principe of Sliding-Mode Control Theory and Intelligent Control Technique in Photovoltaic Systems

Abstract

This chapter presents a PV system composed by a photovoltaic array connected to a DC-DC boost converter with resistive load in order to extract the maximum power generated by the PV panel. This paper presents a model of photovoltaic (PV) system to investigate the P-V characteristics under varying irradiation and temperature conditions. The proposed photovoltaic model is used for evaluating the techniques of maximum power point tracking (MPPT). For this reason, a comparative study between two control methods for maximum power point tracking (MPPT) algorithms in photovoltaic (PV) systems is investigated and well presented. The two MPPT controllers presented in this work are: The Fuzzy Logic Controller (FLC) and the Sliding Mode Controller (SMC). The MPPT controller based on the fuzzy-logic-algorithm is considered as an intelligent technique and it 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 presents, also a very good response for tracking the maximum power point (MPP) for photovoltaic systems. The input parameters that were considered are the voltage and the current. The duty cycle determined by the MPPT controller 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 and via the comparison it is possible to understand the advantages of every controller.