Investigation by simulation and experimental verification of MPPT algorithms for partially shaded stand alone photovoltaic systems [articol]

Abstract

The availability of solar energy varies widely with ambient temperature, different atmospheric and partially shaded conditions. The generated photovoltaic (PV) voltage of each module becomes unequal. Under partially shaded conditions, when the PV module characteristics get more complex with multiple peaks of output power, in such systems, analyzing the performance of maximum power points tracking (MPPT) schemes for independent control of each of the PV modules becomes essential. In this system, the experimental implementation and the MATLAB / SIMULINK based simulations are compared with fuzzy logic control (FLC) and adaptive neurofuzzy inference system (ANFIS) MPPT algorithms in terms of parameters like global peak, tracking speed, power extraction, and harmonic analysis under various partial shading conditions. In this topology, each cascaded Hbridge inverter (CHBMLI) unit is connected to an individual PV module through an interleaved soft switching boost inverter (ISSBC). This topology permits independent control of each PV module to operate at the maximum power point. It also offers another advantage such as lower ripple current and switching loss compared to the conventional boost inverter. The performance of the selective harmonic elimination (SHE) PWM, with a trained ANN sub system for a single phase CHBMLI to generate balanced output voltage even under partially shadowed condition of PV modules is analyzed. The results are evaluated by simulation and experimental implemented on a 300W PV panel prototype with the microcontroller platform. The simulation and hardware results show that ANFIS algorithm is more efficient than the FLC algorithm.