Load matching in a direct-coupled photovoltaic system-application to Thevenin's equivalent loads

摘要

A methodology is developed for the assessment of load matching andfurther estimation of the optimum photovoltaic (PV) arraysarrangement over a prolonged period of time. The method calls forthe calculation of the appropriate effectiveness factor defined asthe ratio of the load energy over the maximum energy that can beproduced by the PV array for a specific time period. Theeffectiveness factor depends on the PV array characteristics, theload characteristics, and the solar irradiance conditions. Toproduce realistic predictions for the effectiveness factor and thePV arrays arrangement with validity over long periods of time, thepresent statistical model describing irradiance employs astochastic variation of solar radiation over a long period of timeand not just a fixed diurnal variation as traditionally done inthe past. Simulations are performed for the case of Thevenin'sequivalent loads. In order to generalize the analysis, thesimulation results are presented in a reduced form based on thevalues of the voltage and current corresponding to the maximumpower of the PV array. The results are presented in multiple-curvecomprehensive plots, which allow to determine the optimumphotovoltaic array panel's arrangement without engagingsophisticated mathematical calculations.