Optimizing the operation of a stand-alone photovoltaic power system with distinctive insolation profiles using an on-line computer

To optimize the operation of an array of solar cells, Z. Zinger and A. Braunstein (IEEE Trans. PAS-100 (1981) 1189 – 1192) approximated the insolation profile by three discrete levels only throughout the day. In our previous two papers, the problem was solved using a clear, but real, insolation profile. This paper presents an accurate and computer-aided algorithm to achieve this optimization continuously for any insolation profile. The computer is programmed so that it can deal with any dynamic changes in the insolation and load demand. Its commands to switch on or off the parallel strings of the array are decided so that the technical constraints imposed will be satisfied. In addition, the daily delivered, stored and total output energies are deduced for two different arrangements of the system. They differ mainly with regard to the battery location with respect to the other subsystems. The numerous results obtained are analysed fully and discussed.