Abstract
The arrangement of diodes in a solar cell array affects the Maximum Power Point (MPP) of the solar cell system. Thus, a pre-wiring method for determining the optimal arrangement of the diodes, which results in the highest MPP, is desirable. This paper proposes a numerical algorithm that predicts the optimal diodes arrangement. A computer program, written in 'Spice', measures the MPP of many different combinations of diode arrangements in a Photovoltaic (PV) array. The program then evaluates the array power harvesting efficiencies. By using the statistics of these results it can then point to the best arrangement of diodes for optimal MPP. A pre-requisite for this method is the knowledge of the electrical characteristics of each photodiode. Simulations and measurements indicate that for an array of 15 diodes (3 parallel columns of 5 diodes in series) the relative improvement achieved by using this method is 15% when compared to the average efficiency of an arbitrarily configured array. One application is for high power PV arrays in which the wiring and optimum arrangement is fixed and the optimal diode arrangement may then be found. Alternatively, for small scale low power PV arrays dynamic real time reconfigurable PV arrays may be realized.
Key words: Photovoltaic (PV) array, Maximum Power Point (MPP), spice, Monte-Carlo, module-mismatch.
