Measurements of power transfer efficiency in CPV cell-array models using individual DC-DC converters

The high degree of non-uniformity in the irradiance distribution over series-connected solar cells is the main obstacle to the development of concentration photovoltaic (CPV) systems using parabolic dishes. In order to overcome the power loss resulting from the current mismatch due to illumination inhomogeneity, we propose a new cell connection with individual DC-DC converters. The aim of this work is to present an experimental procedure to implement this new approach and to demonstrate its advantages with a basic CPV array prototype. Two separate experiments are carried out respectively with real and equivalent-circuit solar cells in order to study the I-V behavior of the connection under different irradiance distributions. The cells working points which yield the highest net power are determined by maximizing the array efficiency by means of a calculation algorithm. The effectiveness of the system is then proved by comparing the output power obtained by field measurement, with the maximum power that could be delivered by the cells array connected in series. In this study, a possible path towards the development of a more effective CPV receiver prototype is outlined.