Methodology for load matching and optimization of directly coupled PV pumping systems

The aim of this work is to develop a methodology for the assessment of load matching and further estimation of the optimum photovoltaic (PV) arrays arrangement for water pumping systems over a prolonged period of time. The method calls for the calculation of the appropriate effectiveness factor defined as the ratio of the load energy over the maximum energy that can be produced by the PV array for a specific time period. The effectiveness factor depends on the PV array characteristics, the load characteristics, and the solar irradiance conditions. To produce realistic predictions for the effectiveness factor and the PV arrays arrangement with validity over long periods of time, the present model takes into account the stochastic variation of solar irradiation over a long period of time and not just a fixed diurnal variation as was traditionally done in the past. In order to generalize the analysis, simulation results must be presented in a reduced form based on the values of the voltage and current corresponding to the maximum power of the PV array. The results can be expressed in multiple-curve comprehensive plots, which allow determining the optimum photovoltaic array panel's arrangement without engaging sophisticated mathematical calculations.