Prospects of using time series to find the maximum power point of a photovoltaic array from its load currents and voltages

Abstract

In this paper an algorithm based on autoregressive (AR) third order time series has been proposed to forecast a photovoltaic (PV) array’s short circuit current and open circuit voltage at a given instant from directly and easily measurable load currents and voltages in shortly spaced three preceding intervals of time. The maximum power point (MPP) of the PV array’s current-voltage characteristic curve corresponding to that instant can then be obtained from the forecasted short circuit current and open circuit voltage. This paper has emphasized on laying the theoretical foundation, achieving preliminary results, their comparison with measured values and identifying further investigations needed for the proposed real-time application of time series which has so far been used mainly for forecasting long term events. The methodology presented in this paper does not lack in generality and can easily be extended to include refinements. It is applicable for a PV array installed at any geographical location either in stand-alone or in grid connected mode