Improved MPPT Algorithm for Controlling a PV System Grid Connected for Rapid Changes of Irradiance

摘要

Single-phase grid connected inverter is one of the inverter types widely used in photovoltaic generation systems (PVGS) because of the benefits it offers. Effective control of PVGS, is given by MPP block, to track the maximum power point (MPPT) of PV modules in order to maximize the power delivered to the grid. However, the electrical voltage supplied by a solar panel depends on climatic conditions and especially irradiation. This paper proposes an improved algorithm of MPP method P&O, widely used thanks to the advantages it presents when there is a uniform insolation. Our improvement is to overcome the P&O limit when there is a rapid change in radiation: generating a reference voltage erroneous (Vref) by MPP block for the DC bus control of inverter. The principle of the algorithm proposed in this work is to make a measurement of periodically Vpv (voltage PV) and Ipv (current PV) to half the interval of the sampling period MPPT. Although this technique requires more computation, it gives accurate results with virtually zero error. The effectiveness of our approach is verified by simulation in Matlab/Simulink for a 1.5Kw inverter connected to the grid.